Peptide hormones are a class of peptides that are secreted into the blood stream and have endocrine functions in living animals. Peptides (from the Greek πεπτος, digestible), are the family of short molecules formed from the linking, in a defined order, of various α-amino acids. ... The endocrine system is a control system of ductless endocrine glands that secrete chemical messengers called hormones that circulate within the body via the bloodstream to affect distant organs. ...

Like other proteins, peptide hormones are synthesized from amino acids according to an mRNA template, which is itself synthesized from a DNA template inside the cell's nucleus. Peptide hormone precursors (pre-prohormones) are then processed in several stages, typically in the endoplasmic reticulum, including removal of the N-terminal signal sequence and sometimes glycosylation, resulting in prohormones. The prohormones are then packaged into membrane-bound secretory vesicles, which can be secreted from the cell by exocytosis in response to specific stimuli. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A hormone (from Greek horman - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... An amino acid residue is what is left of an amino acid once a molecule of water has been lost (an H+ from the nitrogenous side and an OH- from the carboxylic side) in the formation of a peptide bond. ... The interaction of mRNA in a eukaryote cell. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid —usually in the form of a double helix— that contains the genetic instructions specifying the biological development of all cellular forms of life, and most viruses. ... Cells in culture, stained for keratin (red) and DNA (green). ... In cell biology, the nucleus (from Latin nucleus or nuculeus, kernel) is found in all eukaryotic cells and contains the nuclear genes which form most of the cells genetic material. ... The endoplasmic reticulum or ER (endoplasmic means within the cytoplasm, reticulum means little net) is an organelle found in all eukaryotic cells. ... The N-terminal end refers to the extremity of a protein or polypeptide terminated by an amino acid with a free amine group (NH2). ... The term signal sequence can refer to any of the following: protein targeting signal peptide This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Glycosylation is the process or result of addition of saccharides to proteins and lipids. ... A prohormone is a chemical compound that is a precursor to an actual hormone (usually an anabolic like testosterone or some variant), which is taken in order to boost the body’s available hormone supply. ... Exocytosis is the process by which a cell is able to get rid of large molecules or materials including wastes through its membrane. ...

These prohormones often contain superfluous amino acid residues that were needed to direct folding of the hormone molecule into its active configuration but have no function once the hormone folds. Specific endopeptidases in the cell cleave the prohormone just before it is released into the blood stream, generating the mature hormone form of the molecule. Mature peptide hormones then diffuse through the blood to all of the cells of the body, where they interact with specific receptors on the surface of their target cells. Peptidases (proteases [pronounced pro-tea-aces] and proteolytic enzymes are also commonly used) are enzymes which break peptide bonds of proteins. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ...

Notable peptide hormones

Several important peptide hormones are secreted from the pituitary gland. The anterior pituitary secretes luteinizing hormone and follicle stimulating hormone, which act on the gonads, prolactin, which acts on the mammary gland, adrenocorticotrophic hormone (ACTH), which acts on the adrenal cortex to regulate the secretion of glucocorticoids, and growth hormone, which acts on bone, muscle and the liver. The posterior pituitary gland secretes antidiuretic hormone, also called vasopressin, and oxytocin. Peptide hormones are produced by many different organs and tissues, however, including the heart (atrial-natriuretic peptide (ANP) or atrial natriuretic factor (ANF)) and pancreas (insulin and somatostatin), the gastrointestinal tract (cholecystokinin, gastrin), and fat stores (leptin). The anterior pituitary (also called the adenohypophysis) comprises the anterior lobe of the pituitary gland and is part of the endocrine system. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Follicle stimulating hormone (FSH) is a hormone produced by gonadotropes in the anterior pituitary gland. ... 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... Prolactin is a peptide hormone synthesised and secreted by lactotrope cells in the adenohypophysis (anterior pituitary gland). ... Cross section of the breast of a human female. ... Adrenocorticotropic hormone (ACTH or corticotropin) is a polypeptide hormone secreted from corticotropes in the anterior lobe of the pituitary gland in response to corticotropin-releasing hormone (CRH) released by the hypothalamus. ... In mammals, the adrenal glands are the triangle-shaped endocrine glands that sit atop the kidneys. ... The name glucocorticoid derives from early observations that these hormones were involved in glucose metabolism. ... Growth hormone Growth hormone is a polypeptide hormone synthesised and secreted by the anterior pituitary gland which stimulates growth and cell reproduction in humans and other vertebrate animals. ... Grays illustration of a human femur, a typically recognized bone. ... 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. ... The liver is the largest internal organ of the human body. ... The posterior pituitary (also called the neurohypophysis) comprises the posterior lobe of the pituitary gland and is part of the endocrine system. ... Antidiuretic hormone (ADH), or arginine vasopressin (AVP), is a peptide hormone produced by the hypothalamus, and stored in the posterior part of the pituitary gland. ... Oxytocin is a hormone, found in mammals, which in humans is released mainly after stimulation of the nipples or distention of the vagina and which facilitates birth and breastfeeding. ... The heart and lungs, from an older edition of Grays Anatomy. ... Atrial natriuretic factor (ANF), or atrial natriuretic peptide (ANP), is a peptide hormone that is released by walls of the cardiac atrium in response to high NaCl concentration, high extracellular fluid volume, or high blood volume. ... The pancreas is an organ in the digestive system that serves two major functions: exocrine - it produces pancreatic juice containing digestive enzymes. ... The structure of insulin. ... Somatostatin is a hormone. ... Cholecystokinin (from Greek chole, bile; cysto, sac; kinin, move; hence, move the bile-sac (gall bladder)) is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein. ... In humans, gastrin is a hormone that stimulates secretion of gastric acid by the stomach. ... Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... Leptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure (appetite and metabolism). ...

Many neurotransmitters are secreted and released in a similar fashion to peptide hormones, and some 'neuropeptides' may be used as neurotransmitters in the nervous system in addition to acting as hormones when released into the blood. When a peptide hormone binds to receptors on the surface of the cell, a second messenger appears in the cytoplasm. This then makes you poo. Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between a presynaptic and a postsynaptic neuron. ... A Neuropeptide is any of the variety of peptides found in neural tissue; e. ... The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions. ... In biology, second messengers are low-weight diffusible molecules that are used in signal transduction to relay signals within a cell. ... Cytoplasm is like jelly-like material that fills cells. ...