Gonadotropins are protein hormones secreted by gonadotrope cells of the pituitary gland of vertebrates. The two principal gonadotropins are luteinizing hormone (LH) and follicle stimulating hormone (FSH). Both hormones consist of two peptide chains, an alpha chain and a beta chain, linked by disulfide bonds. LH and FSH share nearly identical alpha chains, while the beta chain provides specificity for receptor interactions. 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. ... --72. ... Located at the base of the skull, the pituitary gland is protected by a bony structure called the sella turcica. ... Subgroups †Conodonta Hyperoartia   Petromyzontidae (lampreys) †Pteraspidomorphi †Thelodonti †Anaspida †Cephalaspidomorphi   †Galeaspida   †Pituriaspida   †Osteostraci Gnathostomata (jawed vertebrates)   †Placodermi   Chondrichthyes (cartilaginous fish)   †Acanthodii   Osteichthyes (bony fish)     Actinopterygii (ray-finned fish)     Sarcopterygii (lobe-finned fish)       Actinistia (coelacanths)       Dipnoi (lungfish)       Tetrapoda (four-limbed vertebrates)         Amphibia (amphibians)         Amniota (amniotic embryo)           Sauropsida (reptiles)             Aves (birds)           Synapsida (mammal... Luteinizing hormone (LH) is a hormone synthesised and secreted by gonadotropes in the anterior lobe of the pituitary gland. ... Follicle stimulating hormone (FSH) is a hormone produced by gonadotropes in the anterior pituitary gland. ... 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. ... 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. ...

A third human gonadotropin is human chorionic gonadotropin (hCG), produced by the placenta during pregnancy. Human chorionic gonadotropin (hCG) is a peptide hormone produced in pregnancy, that is made by the embryo soon after conception and later by the trophoblast (part of the placenta). ... The placenta is an ephemeral and temporary organ present only in female placental mammals during gestation (pregnancy). ... Pregnancy Pregnancy is the carrying of one or more embryos or fetuses by female mammals, including humans, inside their bodies. ...

Gonadotropin is sometimes abbreviated Gn. The British spelling is gonadotrophin.

Mechanism

Gonadotropin receptors are embedded in the surface of the target cell membranes and coupled to the G-protein system. Signals triggered by binding to the receptor are relayed within the cells by the cyclic AMP second messenger system. Drawing of a cell membrane A component of every biological cell, the selectively permeable cell membrane (or plasma membrane or plasmalemma) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... G-proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. ... Structure of cAMP Cyclic adenosine monophosphate (cAMP, cyclic AMP or 3-5-cyclic adenosine monophosphate) is a molecule that is important in many biological processes; it is derived from adenosine triphosphate (ATP). ...

Gonadotropins are released under the control of gonadotropin-releasing hormone (GnRH) from the arcuate nucleus of the hypothalamus. The gonads -- testes and ovaries -- are the primary target organs for LH and FSH. The gonadotropins affect multiple cell types and elicit multiple responses from the target organs. As a simplified generalization, LH stimulates the Leydig cells of the testes and the theca cells of the ovaries to produce testosterone (and indirectly estradiol), while FSH stimulates the spermatogenic tissue of the testes and the granulosa cells of ovarian follicles. Gonadotropin-releasing hormone 1 (GNRH1 also called LHRH) is a peptide hormone responsible for the release of FSH and LH from the anterior pituitary. ... In the anatomy of mammals, the hypothalamus is a region of the brain located below the thalamus, forming the major portion of the ventral region of the diencephalon and functioning to regulate certain metabolic processes and other autonomic activities. ... The gonad is the organ that makes gametes. ... 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 egg-producing reproductive organs found in female organisms. ... Luteinizing hormone (LH) is a hormone released by gonadotropes in the anterior lobe of the pituitary gland. ... Follicle stimulating hormone (FSH) is a hormone produced by gonadotropes in the anterior pituitary gland. ... Luteinizing hormone (LH) is a hormone released by gonadotropes in the anterior lobe of the pituitary gland. ... Testosterone is a steroid hormone from the androgen group. ... Estradiol (17-beta estradiol) is a sex hormone. ... Follicle stimulating hormone (FSH) is a hormone produced by gonadotropes in the anterior pituitary gland. ... Human male anatomy The testicles, known medically as testes (singular testis), are the male generative glands in animals. ... A granulosa cell is a supporting cell for the developing female gamete in the ovary of mammals. ... In botany, a follicle is a type of simple dry fruit produced by certain flowering plants. ...

Diseases

Gonadotropin deficiency due to pituitary disease results in hypogonadism. Failure or loss of the gonads usually results in elevated levels of LH and FSH in the blood. Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). ...