Hormonal functions of placenta → Important hormones synthesized by placenta are: Progesterone Estrogen Human placental lactogen (HPL) Human chorionic gonadotropin (hCG) →Others are: Human chorionic thyrotropin Pregnancy specific β, glycoprotein Pregnancy associated plasma protein A (PAPP-A)
Hormonal functions of placenta Read More »
Estrogen → Estrogen cannot be synthesized by placenta alone as it cannot utilize C21 steroid due to lack of enzyme 17 alpha hydroxylase. → Hence conversion of C21 to C19 is not possible (Diczfalusy’s concept). → Fetal adrenal gland produces DHEA-S which is utilized by placental enzymes to synthesize estradiol & estriol. → M/C
Estrogen CHEMISTRY: C18 steroids Secreted as oestradiol SOURCE: Theca and granulosa cells of the Graafian follicles and corpus luteum Adrenal cortex Aromatase enzyme associated with the conversion of androgen to oestrogen in the growing ovarian follicle Post menopausal estrogen production is due to Peripheral aromatization of androstenedione AMOUNT SECRETED: 50 mcg daily Plasma oestradiol level rises 6–7
ESTROGEN Q. 1 Failure of bleeding after withdrawal of oestrogen indicates : A Uterine factor B Ovarian factors C Pituitary factor D Hypothalamic factor Q. 1 Failure of bleeding after withdrawal of oestrogen indicates : A Uterine factor B Ovarian factors C Pituitary factor D Hypothalamic factor Ans. A Explanation: Uterine factor Q. 2 Estrogen replacement for
