GONADOTROPIC SUBSTANCES 



able to very young animals. They also remarked that prolan 

 causes theca luteinization in guinea pigs and rabbits unless 

 ripe follicles are present in the ovaries. The effects of prolan 

 on the ovaries of hypophysectomized rats are also discussed 

 on pages 210-11. 



If prolan is repeatedly administered to adult rats, continu- 

 ous oestrus appears for about a week and is followed by a 

 longer period of partial or complete anoestrus apparently be- 

 cause of persistent progesterone secretion (Katzman and 

 Doisy, 1931; McPhail, 1933). Thus a "hormonal steriliza- 

 tion" may be produced. After injections have been stopped, 

 however, normal oestrous cycles reappear shortly (Sieg- 

 mund, 1934; but Reiprich, 1934, believed recovery to be 

 slower). Evans and Simpson (1929), Zondek (1929), Levin, 

 Katzman, and Doisy (1931), D'Amour and others (1933), 

 and Hoopes (1934) have administered prolan to pregnant 

 rats. Delayed parturition, increased fetal growth, and, com- 

 monly, fetal death were found to be associated with marked 

 luteinization of the ovaries. Selye and others (1934) injected 

 prolan into normal and hypophysectomized pregnant rats. 

 Provided that the pituitary was intact, the injection of pro- 

 lan was followed by a greater ovarian hypertrophy (due to 

 luteinization of the theca and the formation of cystic corpora 

 lutea) in the pregnant rat than in the non-pregnant adult; in 

 lactating rats, chiefly theca luteinization was produced. Ac- 

 cording to von Arvay (1934), prolan diminished or inhibited 

 the movements of the isolated uterus of the pregnant rat. 



The efect of prolan on the genital tract of the female rabbit. — 

 Ovulation characteristically occurs after the intravenous in- 

 jection of prolan into the adult rabbit, especially if the ovaries 

 contain large follicles.'^ If the hormone is administered sub- 

 cutaneously or intraperitoneally, the ovarian changes resem- 

 ble those produced in immature mice and rats. Friedman 



" Normally ovulation in adult rabbits (cats and ferrets) occurs only after coitus, 

 provided that the anterior pituitary is intact. 



[191] 



