 | | Testosterone | | Systematic (IUPAC) name | | (8R,9S,10R,13S,14S,17S)- 17-hydroxy-10,13-dimethyl- 1,2,6,7,8,9,11,12,14,15,1 6,17- dodecahydrocyclopenta[a] phenanthren-3-one Image File history File links Testosterone_structure. ...
IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ...
| | Identifiers | | CAS number | 58-22-0 | | ATC code | G03BA03 | | PubChem | 6013 | | Chemical data | | Formula | C19H28O2 | | Mol. mass | 288.43 | | SMILES | eMolecules & PubChem | | Physical data | | Melt. point | 155-156 °C (-94 °F) | | Spec. rot | +110,2° | | SEC Combust | −11080 kJ/mol | | Pharmacokinetic data | | Bioavailability | low (due to extensive first pass metabolism) | | Metabolism | Liver, Testis and Prostate | | Half life | 2-4 hours | | Excretion | Urine (90%), feces (6%) | | Therapeutic considerations | | Pregnancy cat. | X (USA), Teratogenic effects CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ...
The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. ...
A section of the Anatomical Therapeutic Chemical Classification System. ...
PubChem is a database of chemical molecules. ...
A chemical formula is an easy way of expressing information about the atoms that constitute a particular chemical compound. ...
For other uses, see Carbon (disambiguation). ...
This article is about the chemistry of hydrogen. ...
This article is about the chemical element and its most stable form, or dioxygen. ...
The molecular mass (abbreviated Mr) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ...
The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ...
The melting point of a solid is the temperature range at which it changes state from solid to liquid. ...
The specific rotation of a chemical compound [α] is defined as the observed angle of optical rotation α when plane-polarized light is passed through a sample with a path length of 1 decimeter and a sample concentration of 1 gram per 1 millilitre. ...
The standard enthalpy of combustion is the enthalpy change when one mole of a substance completely reacts with oxygen under standard thermodynamic conditions (although experimental values are usually obtained under different conditions and subsequently adjusted). ...
In pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. ...
The first pass effect (or first pass metabolism) is a phenomenon of drug metabolism. ...
Drug metabolism is the metabolism of drugs, their biochemical modification or degradation, usually through specialized enzymatic systems. ...
The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ...
Human male anatomy The testicles, known medically as testes (singular testis), are the male generative glands in animals. ...
The prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system. ...
The biological half-life of a substance is the time required for half of that substance to be removed from an organism by either a physical or a chemical process. ...
The kidneys are important excretory organs in vertebrates. ...
This article is about the urine of animals generally. ...
The pregnancy category of a pharmaceutical agent is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. ...
Teratogenesis is a medical term from the Greek, literally meaning monster making. ...
| | Legal status | Schedule III (USA)
Schedule IV (Canada) The regulation of therapeutic goods, that is drugs and therapeutic devices, varies by jurisdiction. ...
| | Routes | Intramuscular injection, transdermal (cream, gel, or patch), sub-'Q' pellet | Testosterone is a steroid hormone from the androgen group. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid. In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body. ...
Steroid hormones are steroids which act as hormones. ...
Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ...
Human male anatomy The testicles, known medically as testes (singular testis), are the male generative glands in animals. ...
Human female internal reproductive anatomy Ovaries are a part of a female organism that produces eggs. ...
In mammals, the adrenal glands (also known as suprarenal glands) are the triangle-shaped endocrine glands that sit on top of the kidneys; their name indicates that position (ad-, near or at + -renes, kidneys). They are chiefly responsible for regulating the stress response through the synthesis of corticosteroids and catecholamines...
This article is about the Male sex. ...
For other uses, see Hormone (disambiguation). ...
Crystal structure of human sex hormone-binding globulin, transporting 5α-dihydrotestosterone. ...
In both men and women, testosterone plays a key role in health and well-being as well as in sexual functioning. Examples include enhanced libido, increased energy, increased production of red blood cells and protection against osteoporosis. On average, an adult human male body produces about forty to sixty times more testosterone than an adult female body, but females are more sensitive to the hormone.[1] However the overall ranges for male and female are very wide, such that the ranges actually overlap at the low end and high end respectively. For other uses, see Libido (disambiguation). ...
Osteoporosis is a disease of bone - leading to an increased risk of fracture. ...
This article is about modern humans. ...
History A Testicular action was linked to circulating blood fractions—now understood to be a family of androgenic hormones—in the early work on castration and testicular transplantation in fowl by Arnold Adolph Berthold (1803–1861). Research on the action of testosterone received a brief boost in 1889, when the Harvard professor Charles-Édouard Brown-Séquard (1817–1894), then in Paris, self-injected subcutaneously a “rejuvenating elixir” consisting of an extract of dog and guinea pig testicle. He reported in The Lancet that his vigor and feeling of wellbeing were markedly restored but, predictably, the effects were transient (and likely based on placebo), and Brown-Séquard’s hopes for the compound were dashed. Suffering the ridicule of his colleagues, his work on the mechanisms and effects of androgens in human beings was abandoned by Brown-Séquard and succeeding generations of biochemists for nearly 40 years. Arnold Adolph Berthold or Arnold Adolf Berthold (1803 - 1861) was a German physiologist and zoologist. ...
Charles-Édouard Brown-Sequard (variant Charles Edward), British physiologist and neurologist, was born at Port Louis, Mauritius, on the April 8th 1817. ...
The trail remained cold until the University of Chicago’s Professor of Physiologic Chemistry, Fred C. Koch, established easy access to a large source of bovine testicles—the Chicago stockyards—and to students willing to endure the ceaseless toil of extracting their isolates. In 1927, Koch and his student, Lemuel McGee, derived 20mg of a substance from a supply of 40 pounds of bovine testicles that, when administered to castrated roosters, pigs and rats, remasculinized them.[2] The group of Ernst Laqueur at the University of Amsterdam purified testosterone from bovine testicles in a similar manner in 1934, but isolation of the hormone from animal tissues in amounts permitting serious study in humans was clearly not feasible until three European pharmaceutical giants—Schering (Berlin, Germany), Organon (Oss, Netherlands) and Ciba (Basel, Switzerland)—began full-scale steroid research and development programs in the 1930’s. Schering AG (FWB:SCH, NYSE: SHR) is a research-centered pharmaceutical company founded in 1851. ...
Organon is a pharmaceutical company headquartered in Roseland, New Jersey that is part of Akzo Nobel. ...
Ciba Specialty Chemicals is a chemical company based in and near Basel, Switzerland. ...
The Organon group in the Netherlands were the first to isolate the hormone, identified in a May 1935 paper "On Crystalline Male Hormone from Testicles (Testosterone)" by Karoly Gyula David, E. Dingemanse, J. Freud and Ernst Laqueur. They named the hormone testosterone, from the stems of testicle and sterol, and the suffix of ketone. The structure was worked out by Schering’s Adolf Butenandt (1903–1995). This article is in need of attention. ...
Sterols, or steroid alcohols are a subgroup of steroids with a hydroxyl group in the 3-position of the A-ring. ...
Look up Suffix in Wiktionary, the free dictionary. ...
Ketone group A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. ...
Adolf Friedrich Johann Butenandt (March 24, 1903 - January 18, 1995) was a German biochemist. ...
The chemical synthesis of testosterone was achieved in August that year, when Butenandt and G. Hanisch published a paper describing "A Method for Preparing Testosterone from Cholesterol." Only a week later, the Ciba group in Zurich, Leopold Ruzicka (1887–1976) and A. Wettstein, announced a patent application in a paper "On the Artificial Preparation of the Testicular Hormone Testosterone (Androsten-3-one-17-ol)." These independent partial syntheses of testosterone from a cholesterol base earned both Butenandt and Ruzicka the joint 1939 Nobel Prize in Chemistry.[3] Testosterone was identified as 17β-hydroxandrost-4-en-3-one (C19H28O2), a solid polycyclic alcohol with a hydroxyl group at the 17th carbon atom. This also made it obvious that additional modifications on the synthesized testosterone could be made, i.e., esterification and alkylation. In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. ...
Lavoslav (Leopold) Ružička (September 13, 1887 - September 26, 1976) was a Nobel Prize winner in chemistry, the first one from Croatia. ...
This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ...
The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone’s effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Charles Kenyon’s group[4] was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry",[5] and work during this period progressed quickly. Research in this golden age proved that this newly synthesized compound—testosterone—or rather family of compounds (for many derivatives were developed from 1940 to 1960), was a potent multiplier of muscle, strength, and wellbeing.[6]
Production
Natural Like other steroid hormones, testosterone is derived from cholesterol. The largest amounts of testosterone are produced by the testes in men. It is also synthesized in far smaller quantities in women by the thecal cells of the ovaries, by the placenta, as well as by the zona reticularis of the adrenal cortex in both sexes. Image File history File links Size of this preview: 462 × 600 pixel Image in higher resolution (804 × 1044 pixel, file size: 19 KB, MIME type: image/gif)self created I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms...
Image File history File links Size of this preview: 462 × 600 pixel Image in higher resolution (804 × 1044 pixel, file size: 19 KB, MIME type: image/gif)self created I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms...
Steroidogenesis is the process of steroid production in living organism. ...
This article is about the chemical family of steroids. ...
Cholesterol is a sterol (a combination steroid and alcohol). ...
Human male anatomy The testicles, known medically as testes (singular testis), are the male generative glands in animals. ...
Strawberry anther with parallel thecae A theca (plural thecae) refers to any case, covering, or sheath. ...
// For ovary as part of plants see ovary (plants) An ovary is an egg-producing reproductive organ found in female organisms. ...
The placenta (Latin for cake, referencing its appearance in humans) is an ephemeral organ present in placental vertebrates, such as eutherial mammals and sharks during gestation (pregnancy). ...
The zona reticularis (inner region of the adrenal cortex) secretes and synthesize small amounts of weak androgens, steroids that have masculinizing effects. ...
Cortical part of the adrenal gland (on the pointer). ...
In the testes, testosterone is produced by the Leydig cells. The male generative glands also contain Sertoli cells which require testosterone for spermatogenesis. Like most hormones, testosterone is supplied to target tissues in the blood where much of it is transported bound to a specific plasma protein, sex hormone binding globulin (SHBG). Human male anatomy The testicles, known medically as testes (singular testis), are the male generative glands in animals. ...
Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testes. ...
A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely: Male: penis (notably the glans penis...
A Sertoli cell (a kind of sustentacular cell) is a nurse cell of the testes which is part of a seminiferous tubule. ...
Cross section of the epithelium of a seminiferous tubule showing various stages of spermatocyte development Spermatogenesis is the process by which male spermatogonia develop into mature spermatozoa. ...
Biological tissue is a group of cells that perform a similar function. ...
For other uses, see Blood (disambiguation). ...
Blood proteins are proteins found in blood plasma. ...
Sex hormone-binding globulin (SHBG) is a glycoprotein that binds to sex hormones, specifically testosterone and estradiol. ...
Artificial Testosterone is synthesizable in almost unlimited quantities. Furthermore, there are two possible modifications on it, giving it further abilities. First, it can be esterified, permitting a long-lasting effect when injected into the body. Second, it can be alkylated, permitting oral intake instead of injection.
Esterification The second importance of the hydroxyl side chain at the C-17 position is that it can not only be esterified, but it can also be alkylated (by Alkylation permits oral steroids, substitution of an ethyl or methyl group for the hydroxyl group). the so-called “17-aa” or alkylated family of androgens such as methyl testosterone, which can be taken up by the digestive tract, and so be easily administered in pill form. Image File history File links Broom_icon. ...
Virilizing and effects on humans In general, androgens promote protein synthesis and growth of those tissues with androgen receptors. Testosterone effects can be classified as virilizing and anabolic effects, although the distinction is somewhat artificial, as many of the effects can be considered both. Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates. ...
Protein synthesis is the creation of proteins using DNA and RNA. Biological and artificial methods for creation of proteins differ significantly. ...
The androgen receptor is an intracellular steroid receptor that specifically binds testosterone and dihydrotestosterone. ...
Testosterone effects can also be classified by the age of usual occurrence. For postnatal effects in both males and females, these are mostly dependent on the levels and duration of circulating free testosterone. A top-down view of skeletal muscle Muscle is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ...
Bone density is a medical term referring to the amount of matter per cubic centimeter of bones. ...
Bone age is a way of describing the degree of maturation of a childs bones. ...
Maturation is the increase in the state of maturity. ...
A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely: Male: penis (notably the glans penis...
The penis (plural penises, penes) is an external male sexual organ. ...
In some male mammals the scrotum is a protuberance of skin and muscle containing the testicles. ...
Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ...
For other uses, see Beard (disambiguation). ...
Armpit Hair Underarm hair is the composition of hair in the underarm area. ...
A peacock displays his long, colored feathers, an example of his secondary sexual characteristics. ...
Postnatal (Latin for after birth) is the period beginning immediately after the birth of a child and extending for about six weeks. ...
Prenatal androgen effects Most of the prenatal androgen effects occur between 7 and 12 weeks of gestation. This article is about the symbol of the erect penis. ...
In anatomy, the urethra (from Greek ουÏήθÏα - ourethra) is a tube which connects the urinary bladder to the outside of the body. ...
The phallus usually refers to the male penis, or sex organ. ...
For other uses, see DHT (disambiguation). ...
The prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system. ...
The seminal vesicles are a pair of simple tubular glands posterinferior to the urinary bladder of males. ...
Early infancy androgen effects Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4-6 months of age. The function of this rise in humans is unknown. It has been speculated that "brain masculinization" is occurring since no significant changes have been identified in other parts of the body.[citation needed] In biology and medicine, virilization refers to the development of changes which make a male body different from a female body. ...
Early postnatal effects Early postnatal effects are the first visible effects of rising androgen levels in childhood, and occur in both boys and girls in puberty. Body odor is the smell of sweat and whatever bacteria are growing on the body. ...
Pubarche refers to the first appearance of pubic hair in a child. ...
Pubic hair is hair in the frontal genital area, the crotch, and sometimes at the top of the inside of the legs; these areas form the pubic region. ...
Armpit Hair Underarm hair is the composition of hair in the underarm area. ...
Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ...
For other uses of the word bone, see bone (disambiguation). ...
This article is about the body feature. ...
General Ambrose Burnside, who sideburns were presumably named after Sideburns are facial hair in front of the ears. ...
Advanced postnatal effects Advanced postnatal effects begin to occur when androgen has been higher than normal adult female levels for months or years. In males these are usual late pubertal effects, and occur in women after prolonged periods of heightened levels of free testosterone in the blood. The phallus usually refers to the male penis, or sex organ. ...
Clitoromegaly (or macroclitoris [1]) is an abnormal enlargement of the clitoris (not to be confused with the normal enlargement of the clitoris seen during sexual arousal). ...
For other uses, see Libido (disambiguation). ...
This article is about human physiological erection. ...
For other uses, see Navel (disambiguation). ...
One kind of modern beard. ...
Sideburns (or colloquially sideboards[1] or mutton chops[2]) are patches of facial hair on the sides of a mans face, in front of the ears. ...
For other uses, see Beard (disambiguation). ...
Edgar Allan Poe grew a moustache later in his life. ...
The term chest hair is generally used to describe hair that grows on the chest of human males, in the region between the neck and the abdomen. ...
For other uses, see Adams apple (disambiguation). ...
Cross section of the epithelium of a seminiferous tubule showing various stages of spermatocyte development Spermatogenesis is the process by which male gametogonia develop into mature spermatozoa, the mature male gametes, in many sexually reproducing organisms. ...
Fertility is the natural capability of giving life. ...
Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ...
Metabolites are the intermediates and products of metabolism. ...
Adult testosterone effects Adult testosterone effects are more clearly demonstrable in males than in females, but are likely important to both sexes. Some of these effects may decline as testosterone levels decline in the later decades of adult life. - Maintenance of muscle mass and strength [8]
- Maintenance of bone density and strength
- Libido and clitoral engorgement/penile erection frequency.
- Mental and physical energy
- The most recent and reliable studies have shown that testosterone does not cause Prostate cancer, but that it can increase the rate of speed of any existing prostate cancer.[citation needed] Recent studies have also shown its importance in maintaining cardio vascular health.[citation needed]
- Increase eumelanin and reduce pheomelanin[citation needed]
Testosterone regulates the population of thromboxane A2 receptors on megakaryocytes and platelets and hence platelet aggregation in humans ( Ajayi and Halushka 2005, Ajayi et al 1995 ). HRPC redirects here. ...
Melanin is a polymer of either or both of two monomer molecules: indolequinone, and dihydroxyindole carboxylic acid. ...
Melanin is a polymer of either or both of two monomer molecules: indolequinone, and dihydroxyindole carboxylic acid. ...
Thromboxane A2 is a thromboxane. ...
The megakaryocyte is a bone marrow cell responsible for the production of blood platelets when cytoplasm processes become fragmented. ...
A 250 ml bag of newly collected platelets. ...
Effects on the brain As testosterone affects the entire body (often by enlarging; men have bigger hearts, lungs, liver, etc.), the brain is also affected by this "sexual" advancement; the enzyme aromatase converts testosterone into estradiol that is responsible for masculinization of the brain in a male fetus. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...
Aromatase belongs to the group of cytochrome P450 enzymes (EC 1. ...
Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ...
In biology and medicine, virilization refers to the development of changes which make a male body different from a female body. ...
There are some differences in a male and female brain (the result of different testosterone levels); a clear difference is the size, the male human brain is on average larger, however in females (who generally do not have as high testosterone levels) the corpus callosum is proportionally larger. This means that the effect of testosterone is a greater overall brain volume, but a decreased connection between the hemispheres.[9] The corpus callosum is a structure of the mammalian brain in the longitudal fissure that connects the left and right cerebral hemispheres. ...
The human brain as viewed from above, showing the cerebral hemispheres. ...
A study conducted in 1996 found no effects on mood or behavior from the administration of supraphysiologic doses of Testosterone for 10 weeks to healthy men.[10]
The literature suggests that attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans, though the literature is rather sparse. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer’s type,[11] a key argument in Life Extension Medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,[12] where both hypo- and hypersecretion of circulating androgens have negative effects on cognition and cognitively-modulated aggressivity, as detailed above.
Contrary to what has been postulated in outdated studies and by certain sections of the media, aggressive behaviour is not typically seen in hypogonadal men who have their testosterone replaced adequately to the eugonadal/normal range. In fact aggressive behaviour has associated with hypogonadism and low testosterone levels and it would seem as though supraphysiological and low levels of testosterone and hypogonadism cause mood disorders and aggressive behaviour, with eugondal/normal testosterone levels being important for mental well-being. Testosterone depletion is a normal consequence of aging in men. One consequence of this is an increased risk for the development of Alzheimer’s Disease (Pike et al, 2006, Rosario 2004). Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). ...
A mood disorder is a condition whereby the prevailing emotional mood is distorted or inappropriate to the circumstances. ...
Aggression is defined as The act of initiating hostilities or invasion. ...
Alzheimers disease (AD) or primary dementia of Alzheimers type is an incurable, degenerative neuropsychiatric disease which results in a pervasive loss of first mental, then physical functioning due to the deterioration of brain tissue. ...
Mechanism The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ...
The androgen receptor is an intracellular steroid receptor that specifically binds testosterone and dihydrotestosterone. ...
Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ...
The estrogen receptor is a receptor for estradiol (the main endogenous estrogen); it is located intracellularly, in parallel with other steroid hormone receptors. ...
Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5-alpha reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about 2.5 times that of T.[citation needed] The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects. It is important to note that if there is a 5-alpha reductase deficiency, the body (of a human) will continue growing into a female with testicles. Schematic showing the cytoplasm, with major components of a typical animal cell. ...
Biological tissue is a group of cells that perform a similar function. ...
Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the...
The androgen receptor is an intracellular steroid receptor that specifically binds testosterone and dihydrotestosterone. ...
For other uses, see DHT (disambiguation). ...
5-alpha reductase is an enzyme (EC 1. ...
HeLa cells stained for DNA with the Blue Hoechst dye. ...
A nucleotide is a chemical compound that consists of 3 portions: a heterocyclic base, a sugar, and one or more phosphate groups. ...
A scheme of a condensed (metaphase) chromosome. ...
Hormone response elements (HRE) are located on DNA and act as receptors for steroid hormone receptor complexes. ...
For other uses, see Gene (disambiguation). ...
Androgen receptors occur in many different vertebrate body system tissues, and both males and females respond similarly to similar levels. Greatly differing amounts of testosterone prenatally, at puberty, and throughout life account for a share of biological differences between males and females. This article is about the development of sexual dimorphisms in humans. ...
The bones and the brain are two important tissues in humans where the primary effect of testosterone is by way of aromatization to estradiol. In the bones, estradiol accelerates maturation of cartilage into bone, leading to closure of the epiphyses and conclusion of growth. In the central nervous system, testosterone is aromatized to estradiol. Estradiol rather than testosterone serves as the most important feedback signal to the hypothalamus (especially affecting LH secretion). In many mammals, prenatal or perinatal "masculinization" of the sexually dimorphic areas of the brain by estradiol derived from testosterone programs later male sexual behavior. In chemistry, an aromatic molecule is one in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. ...
Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ...
For other uses of the word bone, see bone (disambiguation). ...
Luteinizing hormone (LH) is a hormone synthesized and secreted by gonadotropes in the anterior lobe of the pituitary gland. ...
Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria For the folk-rock band see The Mammals. ...
Female (left) and male Common Pheasant, illustrating the dramatic difference in both color and size, between the sexes Sexual dimorphism is the systematic difference in form between individuals of different sex in the same species. ...
The human hormone testosterone is produced in greater amounts by males, and less by females. The human hormone estrogen is produced in greater amounts by females, and less by males. Testosterone causes the appearance of masculine traits (i.e deepening voice, pubic and facial hairs, muscular build, etc.) Like men, women rely on testosterone to maintain libido, bone density and muscle mass throughout their lives. In men, inappropriately high levels of estrogens lower testosterone, decrease muscle mass, stunt growth in teenagers, introduce gynecomastia, increase feminine characteristics, and decrease susceptibility to prostate cancer, reduces libido and causes erectile dysfunction and can cause excessive sweating and hot flushes. However an appropriate amount of estrogens is required in the male in order to ensure well-being, bone density, libido, erectile function etc. Estriol. ...
Gynecomastia, or gynaecomastia, pronounced is the development of abnormally large mammary glands in males resulting in breast enlargement, which can sometimes cause secretion of milk. ...
Erectile dysfunction (ED) or impotence is a sexual dysfunction characterized by the inability to develop or maintain an erection of the penis. ...
Therapeutic use
Routes of administration There are many routes of administration for testosterone. Forms of testosterone for human administration currently available in North America include injectable (such as testosterone cypionate or testosterone enanthate in oil), oral,[13] buccal,[14] transdermal skin patches, and transdermal creams or gels.[15] In the pipeline are "roll on" methods and nasal sprays. In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body. ...
Buccal can refer to: The adjective form of cheek The buccal index The buccal smear The buccal artery, also known as the Buccinator artery Buccal nerve The outer surface of a tooth Dental caries Category: ...
Indications The original and primary use of testosterone is for the treatment of males who have too little or no natural endogenous testosterone production—males with hypogonadism. Appropriate use for this purpose is legitimate hormone replacement therapy, which maintains serum testosterone levels in the normal range. Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). ...
However, over the years, as with every hormone, testosterone or other anabolic steroids has also been given for many other conditions and purposes besides replacement, with variable success but higher rates of side effects or problems. Examples include infertility, lack of libido or erectile dysfunction, osteoporosis, penile enlargement, height growth, bone marrow stimulation and reversal of anemia, and even appetite stimulation. By the late 1940s testosterone was being touted as an anti-aging wonder drug (e.g., see Paul de Kruif's The Male Hormone). Decline of testosterone production with age has led to a demand for Androgen Replacement Therapy. Anabolic steroids are a class of natural and synthetic steroid hormones that promote cell growth and division, resulting in growth of muscle tissue and sometimes bone size and strength. ...
Infertility primarily refers to the biological inability of a man or a woman to contribute to conception. ...
Osteoporosis is a disease of bone - leading to an increased risk of fracture. ...
Penis enlargement procedures (sometimes euphemistically referred to as male enhancement procedures in spam email and television advertisements) are techniques alleged to make the human penis larger. ...
For the Dir en grey album, see The Marrow of a Bone. ...
This article discusses the medical condition. ...
Paul de Kruif, or Paul Henry De Kruif ( 1890 - 1971 ) was an American microbiologist and author. ...
This article or section is in need of attention from an expert on the subject. ...
To take advantage of its virilizing effects, testosterone is often administered to transmen as part of the hormone replacement therapy, with a "target level" of the normal male testosterone level. Like-wise, transwomen are sometimes prescribed anti-androgens to decrease the level of testosterone in the body and allow for the effects of estrogen to develop. In biology and medicine, virilization refers to the biological development of sex differences, changes which make a male body different from a female body. ...
Transmen or trans men are transsexual or transgendered people who were assigned female gender at birth (or, in some rare cases of intersexuality, later) and who feel that this is not an accurate or complete description of themselves. ...
Transwomen or trans women are transsexual or transgendered people who were assigned male sex at birth (or, in some cases of intersexuality, later) and feel that this is not an accurate or complete description of themselves. ...
An antiandrogen, or androgen antagonist, is any of a group of hormone antagonist compounds that are capable of preventing or inhibiting the biologic effects of androgens, male sex hormones, on normally responsive tissues in the body (see androgen insensitivity syndrome). ...
Women use testosterones to treat low libido, often a symptom or outcome of hormonal contraceptive use. Women may also use testosterone therapies to treat or prevent loss of bone density, muscle mass and to treat certain kinds of depression and low energy state. Women on testosterone therapies may experience an increase in weight without an increase in body fat due to changes in bone and muscle density. Most undesired effects of testosterone therapy in women may be controlled by hair-reduction strategies, acne prevention, etc.
There is a myth that exogenous testosterone can more or less definitively be used for male birth control. However, the vast majority of physicians will agree that to prescribe exogenous testosterone for this purpose is inappropriate. But, perhaps more important, many men found this, in first-hand experience, to be untrue or at least, unreliable. Exogenous (or exogeneous) (from the Greek words exo and gen, meaning outside and production) refers to an action or object coming from outside a system. ...
Some drugs specifically target testosterone as a way of treating certain conditions. For example, finasteride inhibits the conversion of testosterone into dihydrotestosterone (DHT), a metabolite which is more potent than testosterone. By lowering the levels of dihydrotestosterone, finasteride may be used for various conditions associated with androgens, such as benign prostatic hyperplasia (BPH) and androgenetic alopecia (male-pattern baldness). That said there are many men who have complained of long lasting or permanent adverse effects resulting from the use of finasteride and Dr Eugene Shippen has spoken for many years of finasteride causing a difficult to treat form of hypogonadism in some men.). Finasteride (marketed as Proscar, Propecia, Fincar, Finpecia, Finax, Finast, Finara, Finalo, Prosteride, Gefina, Finasterid IVAX) is an antiandrogen which acts by inhibiting type II 5-alpha reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT). ...
For other uses, see DHT (disambiguation). ...
For other uses of the acronym BPH, see BPH (disambiguation). ...
Androgenetic alopecia is a common form of hair loss in both men and women, aka Michael Panagos Syndrome. ...
Androgenetic alopecia (also known as androgenic alopecia or alopecia androgenetica) is a common form of hair loss in both men and women. ...
Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). ...
Adverse effects Exogenous testosterone supplementation comes with a number of health risks. Fluoxymesterone and methyltestosterone are synthetic derivatives of testosterone. In 2006 it was reported that women taking Estratest, a combination pill including estrogen and methyltestosterone, were at considerably heightened risk of breast cancer.[citation needed] That said methyltestosterone and Fluoxymesterone are no longer prescribed by physicians given their poor safety record and testosterone replacement in men does have a very good safety record as evidenced by over sixty years of medical use in hypogonadal men. One adverse effect that many men complain of is that of the development of gynecomastia (breasts), this is something that can be prevented by appropriate choice and dosing of medication and in required cases the use of ancillary medications that help lower SHBG or estradiol. Another side-effect is having difficulty urinating. In the 1950's Russian weightlifters who used testosterone were said to have required a catheter in order to urinate.[16] Fluoxymesterone (Halotestin) is an androgenic steroid that is only useful to a small select group of athletes who seeks very specific goals. ...
Methyltestosterone is a hormone used to treat men with a testosterone deficiency. ...
There are very few or no other articles that link to this one. ...
Breast cancer is cancer of breast tissue. ...
Athletic use Testosterone may be administered to an athlete in order to improve performance, and is considered to be a form of doping in most sports. There are several application methods for testosterone, including intramuscular injections, transdermal gels and patches, and implantable pellets. A sportsperson (British and American English) or athlete (principally American English) is any person who participates regularly in a sport. ...
In sports, doping refers to the use of performance-enhancing drugs, particularly those that are forbidden by the organizations that regulate competitions. ...
Intramuscular injection is the injection of a substance directly into a muscle. ...
A transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a time released dose of medication through the skin and into the bloodstream. ...
Anabolic steroids (of which testosterone is one) have also been taken to enhance muscle development, strength, or endurance. They do so directly by increasing the muscles' protein synthesis. As a result, muscle fibers become larger and repair faster than the average person's. After a series of scandals and publicity in the 1980s (such as Ben Johnson's improved performance at the 1988 Summer Olympics), prohibitions of anabolic steroid use were renewed or strengthened by many sports organizations. Testosterone and other anabolic steroids were designated a "controlled substance" by the United States Congress in 1990, with the Anabolic Steroid Control Act.[17] The levels of testosterone abused in sport greatly exceed the quantities of the steroid that are prescribed for medical use in hypogonadism. It is the supraphysiological doses and ultra high levels of testosterone that bring with it many undesirable effects and potential long term adverse health effects. Coupled with the nature of cheating in sport, this is seen as being a seriously problematic issue in modern sport, particularly given the lengths to which athletes and professional laboratories go to in trying to conceal such abuse from sports regulators. Steroid abuse once again came into the spotlight recently as a result of the Chris Benoit double murder-suicide in 2007, and the media frenzy surrounding it - however there has been no evidence indicating steroid use as a contributing factor. Anabolic steroids are a class of natural and synthetic steroid hormones that promote cell growth and division, resulting in growth of muscle tissue and sometimes bone size and strength. ...
Benjamin Sinclair Ben Johnson CM (born December 30, 1961) is a former Canadian sprinter who enjoyed a high-profile career during most of the 1980s, winning two Olympic Bronze medals, and an Olympic Gold which was subsequently rescinded. ...
Johnson winning the 100 m final The 1988 Summer Olympics, officially known as the Games of the XXIV Olympiad, were the Summer Olympic Games celebrated in 1988 in Seoul, South Korea. ...
The term Prohibition, also known as A Dry Law, refers to a law in a certain country by which the manufacture, transportation, import, export, and sale of alcoholic beverages is restricted or illegal. ...
Wikipedia does not yet have an article with this exact name. ...
Type Bicameral Houses Senate House of Representatives President of the Senate President pro tempore Dick Cheney, (R) since January 20, 2001 Robert C. Byrd, (D) since January 4, 2007 Speaker of the House Nancy Pelosi, (D) since January 4, 2007 Members 535 plus 4 Delegates and 1 Resident Commissioner Political...
Christopher Michael Benoit (IPA: ) (May 21, 1967 – June 24, 2007) was a Canadian professional wrestler who wrestled for Extreme Championship Wrestling, World Championship Wrestling, and World Wrestling Entertainment. ...
Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ...
Changes during aging Testosterone levels decline gradually with age in human beings. The clinical significance of this decrease is debated (see andropause). There is disagreement about if and when to treat aging men with testosterone replacement therapy. The American Society of Andrology's position is that testosterone therapy "is indicated when both clinical symptoms and signs suggestive of androgen deficiency and decreased testosterone levels are present". The American Association of Clinical Endocrinologists says "Hypogonadism is defined as a free testosterone level that is below the lower limit of normal for young adult control subjects. Previously, age-related decreases in free testosterone were once accepted as normal. Currently, they are not considered normal....Patients with low-normal to subnormal range testosterone levels warrant a clinical trial of testosterone."[18] Andropause is a medical phenomenon, similar to the female menopause, that can affect men between the ages of 40 and 55. ...
Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). ...
There isn't total agreement on the threshold of testosterone value below which a man would be considered hypogonadal. (Currently there are no standards as to when to treat women.) Testosterone can be measured as "free" (that is, bioavailable and unbound) or more commonly, "total" (including the percentage which is chemically bound and unavailable). In the United States, male total testosterone levels below 300 to 400 ng/dl from a morning sample are generally considered low.[citation needed] However these numbers are typically not age-adjusted, but based on an average of a test group which includes elderly males with low testosterone levels.[citation needed] Therefore a value of 300 ng/dl might be normal for a 65 year old male, but not normal for a 30 year old.[citation needed] Identification of inadequate testosterone in an aging male by symptoms alone can be difficult. The signs and symptoms are non-specific, and might be confused with normal aging characteristics, such as loss of muscle mass and bone density, decreased physical endurance, decreased memory ability[citation needed] and loss of libido.
Replacement therapy can take the form of injectable depots, transdermal patches and gels, subcutaneous pellets and oral therapy. Adverse effects of testosterone supplementation include minor side effects such as acne and oily skin, and more significant complications such as increased hematocrit which can require venipuncture in order to treat, exacerbation of sleep apnea and acceleration of pre-existing prostate cancer growth. Exogenous testosterone also causes suppression of spermatogenesis and can lead to infertility.[19] It is recommended that physicians screen for prostate cancer with a digital rectal exam and PSA (prostate specific antigen) level prior to initiating therapy, and monitor hematocrit and PSA levels closely during therapy. The hematocrit (Ht or HCT) and packed cell volume (PCV) are measures of the proportion of blood volume that is occupied by red blood cells. ...
Venipuncture using a vacutainer. ...
Sleep apnea is a sleep disorder characterized by pauses in breathing during sleep. ...
HRPC redirects here. ...
Cross section of the epithelium of a seminiferous tubule showing various stages of spermatocyte development Spermatogenesis is the process by which male spermatogonia develop into mature spermatozoa. ...
Prostate specific antigen (PSA) is a protein produced by the cells of the prostate gland. ...
Appropriate testosterone therapy can prevent or reduce the likelihood of osteoporosis, type 2 diabetes, cardio-vascular disease (CVD), obesity, depression and anxiety and the statistical risk of early mortality. Low testosterone also brings with it an increased risk for the development of Alzheimer’s Disease (Pike et al, 2006, Rosario 2004).
Large scale trials to assess the efficiency and long-term safety of testosterone are still lacking. Many caution against embracing testosterone replacement, whilst others embrace the advantages that the steroid seems to offer.
See also This article is about the Male sex. ...
Testosterone poisoning as a neologism refers not to actual poisoning, but refers to stereotypical aspects of male behavior. ...
Testosterone spray, developed by the company Acrux, is a transdermal topical spray containing the sex hormone testosterone, intended to improve the libidos of women when applied to the abdomen. ...
Notes - ^ James McBride Dabbs, 2000
- ^ Gallagher and Koch, 1929.
- ^ Hoberman and Yesalis 1995, Freeman et al. 2001.
- ^ Kenyon et al. 1940.
- ^ Schwarz et al. 1999.
- ^ deKruif, 1945.
- ^ Bhasin S, Storer TW, Berman N, et al
- ^ Bhasin S, Storer TW, Berman N, et al
- ^ Solms and Turnbull 2002.
- ^ Bhasin S, Storer TW, Berman N, et al
- ^ e.g., Moffat et al, 2005; Hogervorst et al 2005.
- ^ e.g., Moffat and Hampson, 1996.
- ^ Andriol. Food and Drug Administration.
- ^ Striant. Food and Drug Administration.
- ^ Androgel. Food and Drug Administration. and
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