A group of male or female reproductive cells, which in jellyfish often line the sides of the stomach, but mayextend through the bell of a jellyfish in the most mature specimens, especially the chirodropids.... gonad
A glycoprotein hormone secreted by the PLACENTA in early pregnancy, and stimulating the CORPUS LUTEUM within the ovary (see OVARIES) to secrete OESTROGENS, PROGESTERONE, and relaxin. The hormone is essential for the maintenance of pregnancy up to about 6–8 weeks of gestation. A RADIOIMMUNOASSAY can be used to detect its presence, and pregnancy can be diagnosed as early as six days after conception by testing for it in the urine. Some tumours also secrete human chorionic gonadotrophin, particularly HYDATIDIFORM MOLE, which produces large amounts.... human chorionic gonadotrophin
... chorionic gonadotrophic
Gonadotrophins, or gonadotrophic hormones, are hormones that control the activity of the gonads (i.e. the testes and ovaries). In the male they stimulate the secretion of TESTOSTERONE and the production of spermatozoa (see SPERMATOZOON); in the female they stimulate the production of ova (see OVUM) and the secretion of OESTROGENS and PROGESTERONE. There are two gonadotrophins produced by the PITUITARY GLAND. CHORIONIC GONADOTROPHIC HORMONE is produced in the PLACENTA and excreted in the urine.... gonadotrophins
Hormones that stimulate cell activity in the ovaries and testes. Gonadotrophins are essential for fertility. The two most important gonadotrophins are follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are secreted by the pituitary gland. Another gonadotrophin, HCG (see gonadotrophin, human chorionic), is produced by the placenta during pregnancy. Certain gonadotrophins are used as drugs in the treatment of infertility.... gonadotrophin hormones
A hormone produced by the placenta in early pregnancy. Human chorionic gonadotrophin (HCG) stimulates the ovaries to produce oestrogen and progesterone, which are needed for a healthy pregnancy. HCG is excreted in the urine, and its presence in urine is the basis of pregnancy tests on urine samples. ... gonadotrophin, human chorionic
The sex glands – the testes in men and the ovaries in women.... gonads
see Turner’s syndrome.... gonadal dysgenesis
n. the period during which the gonads begin to secrete sex hormones, so triggering puberty. The timing for this event is controlled by the pituitary gland; gonadarche occurs usually between the ages of 10 and 11 in girls and 11 and 12 in boys.... gonadarche
(GnRH analogue, LHRH analogue) any one of a group of analogues of *gonadotrophin-releasing hormone (gonadorelin), which stimulates release of the gonadotrophins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. They are more powerful than the naturally occurring hormone, initially increasing the secretion of gonadotrophins by the pituitary: this acts to block the hormone receptors and to inhibit the release of further gonadotrophins, which suppresses production of oestrogens and androgens. Gonadorelin analogues include *buserelin, *goserelin, leuprorelin, and triptorelin. They are used in the treatment of endometriosis, fibroids, and some types of infertility. GnRH analogues are also used in the treatment of advanced prostate cancer. After causing an initial rise in plasma testosterone for approximately ten days the level then falls to the same low level as that achieved by castration. Because the initial flare in testosterone may cause an acute enlargement of the cancer, *anti-androgens are given usually for the first two weeks following the first injection of the gonadorelin analogue.... gonadorelin analogue
(gonadotrophic hormone) n. any of several hormones synthesized and released by the pituitary gland that act on the testes or ovaries (gonads) to promote production of sex hormones and either sperm or ova. Their production is controlled by *gonadotrophin-releasing hormone. The main gonadotrophins are *follicle-stimulating hormone and *luteinizing hormone. They may be given by injection to treat infertility. See also human chorionic gonadotrophin.... gonadotrophin
(GnRH, gonadorelin) a peptide hormone produced in the hypothalamus and transported via the bloodstream to the pituitary gland, where it controls the synthesis and release of pituitary *gonadotrophins. It may be used to test the ability of the pituitary to produce gonadotrophins. *Gonadorelin analogues are used to treat endometriosis, fibroids, some types of infertility, and prostate cancer.... gonadotrophin-releasing hormone
commercially available preparations of *follicle-stimulating hormone and *luteinizing hormone. They are used mainly to treat infertility in women with gonadotrophin deficiency due to hypopituitarism and to stimulate superovulation in women undergoing in vitro fertilization.... human menopausal gonadotrophins
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