THE PITUITARY BODY 



tary implants, prolan, or pregnant-mare serum) or by andro- 

 gens (androsterone or extract of male urine or bull testis) . Why 

 androgens should have this effect on spermatogenesis is not 

 known; in view of other work in the rat it is reasonable to be- 

 lieve that an action on the testicular germinal epithelium is 

 important. Recent studies of the action of gonadotropic sub- 

 stances^-' in immature rats have been made by Moore (1936) 

 and Price (1936). Price compared the effects of pituitary im- 

 plants and prolan in very young rats. The indirect effect on 

 the seminal vesicles was accompanied by less change in the 

 apparent amount of interstitial tissue after pituitary im- 

 plants than after prolan. Prolonged injection of the latter 

 caused damage to the germinal epithehum. Moore found 

 that sheep pituitary and pregnant-mare serum, like prolan, 

 brought about no precocious spermatogenesis in normal im- 

 mature rats. The most marked effects were on the inter- 

 stitial cells and secondary organs; although the seminal vesi- 

 cles might weigh fifty times as much as those of non-injected 

 rats, the testicular weight was never more than doubled. 

 Little change of either type was produced in adult animals. 



Follicle-stimulating extract (from the urine after gonad- 

 ectomy or after the menopause) was injected by Huberman, 

 Israeloff, and Hymovitz (1937) into men with sterility caused 

 by an endocrine disturbance (300-2,000 rat-units as 50 rat- 

 units twice weekly). The treatment appeared to cause an in- 

 crease in the number and motility of the spermatozoa but 

 did not correct the sterility. 



Using normal rats 21 days old and hypophysectomized rats 

 2^ days old (7 days after hypophysectomy), Creep, Fevold, 

 and Hisaw (1936) compared the effects on the male reproduc- 

 tive organs of follicle-stimulating extract and luteinizing ex- 

 tract made by them from sheep pituitary. They concluded 

 that the follicle-stimulating extract had no effect on the inter- 

 stitial tissue but caused increased mitotic division of the cells 

 of the germinal epithelium so that spermatogenesis could be 



^^ Pituitary homo-implants, sheep pituitary, prolan, and pregnant-mare serum. 



[74I 



