GONADS AND THE PITUITARY BODY 



Wolfe and Cleveland (1931) and Hill (1934) have esti- 

 mated, under various conditions, the amount of gonadotropic 

 hormone in the anterior pituitary of the rabbit. They used as 

 their test the production of ovulation in adult rabbits. The 

 anterior pituitary of rabbits 3 months old contained near- 

 ly as much hormone as that of the adult. The pituitaries of 

 rabbits about i month old clearly contained less hormone 

 than that of animals more than 3 months old. Hill found that 

 the anterior pituitary of the adult female rabbit contained 

 more gonadotropic hormone than did that of the adult male.'* 

 He also determined the concentration of the hormone in the 

 pituitary of adult female rabbits under different conditions of 

 sexual activity. The concentrations of hormone found were 

 as follows:"' during oestrus, 156; 30 minutes after mating, 

 122; 24 hours after mating, 21 ; pregnant, 15 days, 250; 

 pseudopregnant, 10 days, 250. At other times of pregnancy 

 and pseudopregnancy, lower concentrations of hormone were 

 found (83-100 units). Immediately postpartum, the concen- 

 tration was about 133 units. In general, the total amount of 

 hormone in a single pituitary varied similarly. 



Five to seven hours after the administration of an extract 

 of the anterior pituitary of the ox, uterine movements of the 

 unanesthetized rabbit are markedly reduced. This effect 

 does not depend upon an ovarian change, for it occurs in 

 ovariectomized does (Reynolds, 1932). Robson (1931-32) 

 studied the uterine response to the oxytocic and pressor hor- 

 mones of the pars neuralis in rabbits in which corpora lutea 

 with subsequent pseudopregnancy had been produced by the 

 administration of implants or extracts of the pars glandularis. 

 The uterus of typical pseudopregnancy does not contract in 

 the presence of the oxytocic hormone; the pressor hormone 

 causes a reduction in uterine tone. In Robson's animals, in 



•8 But see Table V. 



_,, . , J • ■• • (Units per gram) 



" 1 he concentrations are here expressed in arbitrary units . 



10 



[137] 



