Chorionic Gonadotropin(redirected from placentagonadotropin)
Also found in: Dictionary, Medical.
chorionic gonadotropin[‚kȯr·ē′än·ik gō‚nad·ə′trō·pən]
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.