THE GONADOTROPIC HORMONES 



sidered opinion of investigators like Rowlands is that an im- 

 mune-like reaction has been neither proved nor ruled out. 



Several attempts to inhibit the effects of gonadotropic hor- 

 mones secreted by the pars glandularis in situ have been suc- 

 cessful and constitute evidence favorable to the view that 

 antihormone-formation is important physiologically, Parkes 

 and Rowlands (1936) showed that the ovulation which usual- 

 ly follows coitus in the rabbit can be prevented by the intra- 

 venous injection, 15 minutes after mating, of rabbit serum 

 containing a high titer of antihormones toward the gonado- 

 tropic principles in ox anterior pituitary extract. An exten- 

 sion of this study by Rowlands (1937) indicated that such 

 serum containing antihormone, although not interfering with 

 corpus luteum formation, pregnancy, or lactation in the 

 mouse or rat, did have the following antigonadotropic effects: 

 (i) it prevented ovulation in the prepubertal rat, (2) it pro- 

 duced atrophy of the reproductive organs of the adult male 

 rat, and (3) it could prevent, in the rabbit, ovulation or cor- 

 pus luteum formation or, in pregnant animals, implantation 

 of the blastocyst or fetal survival. According to Collip ( 1 937) , 

 antihormone-containing serum prevents oestrous cycles in 

 rats. Also he believed (1935) that antihormone-like sub- 

 stances may appear in the blood spontaneously. Thompson 

 and Gushing (1937) caused marked ovarian atrophy in grow- 

 ing rats by injecting serum containing antihormone (sheep 

 pituitary extract as "antigen" for about two months). Hisaw, 

 Hertz, and Fevold (1936) concluded that, although the con- 

 tinued injection of sheep pituitary extract might be accom- 

 panied by a refractory condition of the ovaries in juvenile 

 monkeys {Macaca mulatto), only temporary effects were pro- 

 duced in adults. They believed that the antihormone pro- 

 of ovulation in the rabbit as an indication of gonadotropic effect. However, Parkes 

 and Rowlands used a saline suspension of the sheep pituitary body. 



More clear cut are the experiments of Rowlands (1938) who found that the 

 serum of an animal receiving a course of injections of pituitary extract might aug- 

 ment the effects of the extract in immature rats (ovarian hypertrophy) and yet 

 inhibit the action of the extract in rabbits (ovulation response). 



[113I 



