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ANIMAL BIOCHEMISTRY 



OVARIES. The cyclic phenomenon of menstruation in the human 

 female is stimulated by a hormone called estrone. This hormone is 

 produced in the growing ovarian follicle. The growth of the follicle, 

 in turn, is stimulated by a gonadotropic hormone produced by the 

 anterior lobe of the pituitary gland. The rupture of the follicle lib- 

 erates the ovum, which passes to the uterus by way of the Fallopian 

 tube. The ruptured follicle then develops into a yellow body called 

 the corpus luteum, which in turn produces a hormone called proges- 

 terone. If the ovum is not fertilized, the corpus luteum grows for a 

 few days and then gradually disappears to be replaced at monthly 

 intervals by new follicles and ova. 



Modern chemistry has identified a number of estrogenic compounds, 

 among which are (1) estrone or theelin, (2) estriol or theelol, (3) 

 estradiol or dihydrotheelin, (4) equilin, and (5) equilenin. These 

 estrogens are steroids. 



OH 



estrone 



estriol 



estradiol 



Some investigators believe that the more potent estradiol is the true 

 ovarian hormone which is converted to estrone, and that estriol is 

 formed from estrone. The body seems to tise glucuronic acid to detoxi- 

 cate estriol, forming physiologically inactive estriol glucuronate, which 

 is excreted. The corpus luteum hormone, progesterone, continues 

 uterine changes which were initiated by the estrogenic hormones, 

 estrone and estradiol. Implantation of the fetus on the wall of the 

 uterus does not occur if progesterone production is lacking. 



