| 释义 |
chorionic gonadotropin
chorion′ic gonadotro′pin
n. gonadotropin produced and secreted by the chorion. Compare human chorionic gonadotropin. Chorionic Gonadotropin
chorionic gonadotropin[‚kȯr·ē′än·ik gō‚nad·ə′trō·pən] (biochemistry) human chorionic gonadotropin Chorionic Gonadotropin a hormone produced by the villi of the chorion and the placenta in some of the higher apes and in man. It is a complex protein (glycoprotein) containing the carbohydrates galactose (10.7 percent) and hexosamine (5.2 percent) and having a molecular weight of approximately 100,000. Chorionic gonadotropin has a stimulating effect on the corpus luteum, causing it to grow in size, increasing its secretory activity and prolonging its life; it converts the corpus luteum into the corpus luteum of pregnancy, which continues to secrete the hormone progesterone until the placenta is fully formed. Chorionic gonadotropin, while similar in effect to the luteinizing hormone of the pituitary, differs from it in certain respects: it does not restore gonads atrophied after removal of the pituitary, it has no effect on avian gonads, and it causes only a slight enlargement of the ovaries in immature rodents. chorionic gonadotropin
gonadotropin [go´nah-do-tro″pin] any hormone having a stimulating effect on the gonads. Two such hormones are secreted by the anterior pituitary gland" >pituitary gland: follicle-stimulating hormone and luteinizing hormone, both of which are active, but with differing effects, in the two sexes. Called also gonadotropic hormone.chorionic gonadotropin (human chorionic gonadotropin (HCG) (hCG)) 1. a glycopeptide hormone that is produced by cells of the fetal placenta and maintains the function of the corpus luteum during the first few weeks of pregnancy. It is thought to promote steroidogenesis in the fetoplacental unit and to stimulate fetal testicular secretion of testosterone. It can be detected by immunoassay in the maternal urine within days after fertilization; this provides the basis for the most commonly used pregnancy test.2. the same principle obtained from the urine of pregnant women, used in treatment of certain cases of cryptorchidism and male hypogonadism, to induce ovulation and pregnancy in certain infertile, anovulatory women, and to increase the numbers of oocytes for patients attempting conception using technologies" >assisted reproductive technologies such as transfer" >gamete intrafallopian transfer or fertilization" >in vitro fertilization; administered intramuscularly. See also choriogonadotropin alfa.cho·ri·on·ic go·nad·o·tro·pin (CG), a glycoprotein with a carbohydrate fraction composed of d-galactose and hexosamine, extracted from the urine of pregnant women and produced by the placental trophoblastic cells; its most important role appears to be stimulation, during the first trimester, of ovarian secretion of the estrogen and progesterone required for the integrity of conceptus; it appears to play no significant role in the last two trimesters of pregnancy, as the estrogen and progesterone are then formed by the placenta. CG has luteinizing hormone activity and exerts its actions through luteinizing hormone receptors. Synonym(s): β-HCG, choriogonadotropin, chorionic gonadotropic hormone, chorionic gonadotrophic hormone, placenta gonadotropin, placentagonadotropinchorionic gonadotropin Human chorionic gonadotrophin A hormone secreted by the anterior pituitary gland, which supports pregnancy Components α-hGH 14.5 kD; β-hGH 22.2 kD. See FSH, Gonadotropin, LH. Chorionic gonadotropin levels–post conception Weeks IU/L 1 wks 5-50 2 wks 40-1000 3 wks 100-4000 4 wks 800-10,000 5-6 wks 5000-100,000 8 wks 20,000-200,000 9-12 wks 10,000-200,000 2nd trimester 8,000-50,000 3rd trimester 6,000-50,000 cho·ri·on·ic go·nad·o·tro·pin (kōr'ē-on'ik gō-nad'ō-trō'pin) A glycoprotein with a carbohydrate fraction composed of d-galactose and hexosamine, produced by the placental trophoblastic cells; its most important role appears to be stimulation (during the first trimester) of ovarian secretion of the estrogen and progesterone required for the integrity of the conceptus; it appears to play no significant role in the last two trimesters of pregnancy, because the estrogen and progesterone are then formed by the placenta. Testing for the beta fraction of human chorionic gonadotropin is the basis for most serum and urine pregnancy tests.
Synonym(s): anterior pituitarylike hormone, chorionic gonadotropic hormone, chorionic gonadotrophic hormone. cho·ri·on·ic go·nad·o·tro·pin (kōr'ē-on'ik gō-nad'ō-trō'pin) Glycoprotein with carbohydrate fraction composed of d-galactose and hexosamine, extracted from the urine of pregnant women. FinancialSeeCGThesaurusSeehuman chorionic gonadotropin |