GONADOTROPIC SUBSTANCES 



the injection of prolan halted the normal development of the 

 follicle. Other abnormalities of the ovary attributed to the 

 treatment were the formation of cystic follicles, which often 

 contained blood, and luteinization of the theca interna. The 

 atretic corpora lutea were occasionally hemorrhagic. Pratt 

 believed that the most characteristic sequel of prolan-admin- 

 istration was the formation of an increased number of atretic 

 follicles. 



The efect of prolan on the mammary gland. — In animals in 

 which typical pseudopregnancy can be produced by the in- 

 jection of prolan, concomitant hypertrophy of the nipples and 

 breasts also occurs (e.g., rabbit and cat) and is said sometimes 

 to be accompanied by the secretion of milk (Reiss and Lang- 

 endorf, 1929). Selye, Collip, and Thomson (1933) produced 

 marked development of the mammary glands of rats by in- 

 jecting 200 rat-units of prolan daily for 26-53 days. No secre- 

 tion of milk occurred. However, large amounts of milk were 

 secreted if the ovaries of the injected animals were removed. 

 The release of the secreting mechanism by ovariectomy did 

 not occur in injected animals which were simultaneously 

 hypophysectomized. Enzmann and Pincus (1933) reported 

 that the injection of small doses of prolan into nursing mice 

 affected milk-secretion unfavorably. Prolan was observed to 

 have a similar effect on lactation in ovariectomized mice (De 

 Jongh, 1933). On the other hand, Majert (1932) believed 

 that more milk was secreted by pigs, in which there was a 

 deficiency of secretion, if prolan was administered. Koch 

 (1934) administered prolan to sheep and cows but observed 

 no effect on the mammary glands before or during lactation. 



Changes in the genital tract of male animals following the 

 administration of prolan. — The primary and only important 

 effect of prolan in male animals is on the testis. As in female 

 animals, castration prevents the secondary changes in the 

 accessory sexual organs. Prolan has no stimulating effect on 

 spermatogenesis in immature male mammals but does stimu- 



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