gonadotropic hormone

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gonadotropic hormone

(gō'nădətrŏp`ĭk) or

gonadotropin,

any one of three glycoprotein (see proteinprotein,
any of the group of highly complex organic compounds found in all living cells and comprising the most abundant class of all biological molecules. Protein comprises approximately 50% of cellular dry weight.
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) hormoneshormone,
secretory substance carried from one gland or organ of the body via the bloodstream to more or less specific tissues, where it exerts some influence upon the metabolism of the target tissue.
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 released by either the anterior pituitary glandpituitary gland,
small oval endocrine gland that lies at the base of the brain. It is sometimes called the master gland of the body because all the other endocrine glands depend on its secretions for stimulation (see endocrine system).
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 or the placenta (the organ in which maternal and fetal blood exchange nutrients and waste products) that have various effects upon the ovariesovary,
ductless gland of the female in which the ova (female reproductive cells) are produced. In vertebrate animals the ovary also secretes the sex hormones estrogen and progesterone, which control the development of the sexual organs and the secondary sexual characteristics.
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 and testes (see testistestis
or testicle
, one of a pair of glands that produce the male reproductive cells, or sperm. In fetal life the testes develop in the abdomen, then descend into an external sac, the scrotum.
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). Gonadotropin-releasing hormone (Gn-RH) is produced and released from the hypothalamus. Gn-RH release stimulates the secretion of both follicle-stimulating hormone (FSH) and lutenizing hormone (LH) from the pituitary gland. Gn-RH is a peptide composed of ten amino acids which are synthesized in the hypothalamus (that portion of the brain nearest the pituitary). This hormone travels in the bloodstream to the anterior pituitary, where it causes the release of the gonadotropic hormones. The hormones FSH and LH inhibit the amount of Gn-RH released by a mechanism called "negative feedback." In the female, FSH causes an increase in the weight of the ovaries and encourages the growth of Graafian follicles (containing maturing eggs); in males, FSH produces spermatogenesis in the testes. In females, secretion of LH is associated with the maturation of the follicles, the manifestation of heat (or estrus), and the release of the egg from the follicle, which is transformed into a corpus luteum. In males, LH stimulates the testes to release testosterone. Sex hormones released from the ovaries and testes eventually reach the hypothalamus and help to regulate the hormonal cycle. Human chorionic gonadotropin (HCG), produced in the placenta, helps to maintain pregnancy once a fetus begins to develop. It appears in the urine in approximately the first week after the first missed menstrual period, and is the basis for two kinds of pregnancy tests; in the Ascheim-Zondek testm it causes the ovaries of an immature female rat or mouse to gain weight and produce ripened follicles, and in the Friedman test, it stimulates female rabbits to ovulate.

gonadotropic hormone

[gō¦nad·ə¦träp·ik ′hȯr‚mōn]
(biochemistry)
Either of two adenohypophyseal hormones, FSH (follicle-stimulating hormone) or ICSH (interstitial-cell-stimulating hormone), that act to stimulate the gonads.
References in periodicals archive ?
[26.] Nobrega RH, de Jesus LWO, Honji RM, Borella MI (2016) Characterization of gonadotropic cells during continuous and seasonal spermatogenesis of two freshwater fish species: a histochemical and immunohistochemical study.
The ameliorative effect of hEIF extract on precocious puberty was examined by comparing body weights, bone mineral densities, and gonadotropic hormone levels between the experimental and control groups, which are reflective of the changes in pubertal growth and endocrine function.
Certainly, men with primary hypogonadism (without testicular function) cannot respond to clomiphene-induced gonadotropic hormones.
As one of the most important gonadotropic hormones in adult insects, 20E plays a critical role in the immediate control of oogenesis (Bownes 1989).
For example, successful gonad maturity has been developed in captivity; spawning have been obtained through the application of Human gonadotropic hormone (HGH) and high fertilization and hatching rates (>90% and >85% respectively) have been obtained as well (Pintos-Teran et al., 2003; Dumas et al, 2004).
Somatotropic and gonadotropic axis linkages in infancy, childhood, and the puberty-adult transition.
after 13 days post-infection and vertical transmission could be detected in the 2nd gonadotropic cycle (33).
The luteinizing hormone, gonadotropic releasing hormone, and testosterone all are dropping below what's considered normal.
Tena-Sempere (2006) .Expression of hypothalamic KiSS-1 system and rescue of defective gonadotropic responses by kisspeptin in streptozotocin- induced diabetic male rats.Diabetes.
Moreover, in male patients with idiopathic hemochromatosis, testicular atrophy has been suggested to be caused by insufficient secretion of gonadotropins due to the selective accumulation of iron in gonadotropic cells of the pituitary gland [44].
Although others had described a gonadotropic substance present in the placenta, it was Aschheim and Zondek who discovered hCG in the urine in their demonstration of ovarian stimulation of immature female mice injected with the urine of pregnant women (2, 3).