THE GONADOTROPIC HORMONES 



tary hypertrophy. There is Httle basis for interpreting these 

 observations, although Bokslag beHeved that progesterone, 

 Hke many other substances, lessens the gonadotropic potency 

 of the pituitary. Moreover, Laroche, Simmonet, and Bom- 

 pard (1937) found that progesterone''^ lessens the urinary ex- 

 cretion of gonadotropic hormone in spayed women or women 

 past the menopause and concluded that its effect therefore 

 resembles that of oestrone. The corpus luteum hormone ap- 

 pears not to affect the testis or secondary sexual organs of 

 immature male rats (Pels, 1936). Pels, however, injected 

 small doses of progesterone (1.2-1.7 mg. as the total dose 

 during 1 1-22 days). 



A few observations in other animals require mention. 

 Dempsey (1937) reported that preovulatory swelling and 

 ovulation are prevented in the guinea pig by the administra- 

 tion of progesterone (0.05 LU. daily for 20 days). Follicular 

 growth was not inhibited by the hormone. In the rabbit, also, 

 the injection of progesterone prevents ovulation after coitus, 

 although it appears not to diminish the ovulation-producing 

 effect of prolan-*^ (Makepeace, Weinstein, and Friedman, 

 1936-37). These observations extend and confirm earlier re- 

 ports such as that of Mahnert. 



c) Androgenic substances such as hormones extracted from 

 the testes or urine or derivatives of these. '^'^ — Breneman (1937) 

 studied the effects of androgens on the chick receiving injec- 

 tions between the fifth and tenth days after hatching. Ob- 

 servations were continued to an age of 30 days. Substances 

 such as testosterone or dihydroandrosterone benzoate pre- 

 vented testicular growth during the injection period. How- 

 ever, three weeks after injections were stopped, the testes 

 weighed almost twice as much as those of non-injected chicks. 

 The author also concluded that dihydroandrosterone ben- 



''s Total doses of 25-58 mg. of progesterone as 5-23 injections over 1 1-144 days. 



••* In pregnant does, the dose of prolan or extract of the pars glandularis required 

 to produce ovulation is larger than in oestrous rabbits. 



''' Testosterone or androstenedione can cause ovulation by acting on the excised 

 ovary of the toad, X. laevis (Shapiro and Zwarenstein, 1937). 



