GONADS AND THE PITUITARY BODY 



implants or extracts of the anterior pituitary on the gonads 

 of immature, young adult, and senile male mice or rats indi- 

 cates that the chief effect is on the interstitial cells. As a re- 

 sult of treatment, an increased amount of testicular hormone 

 is liberated, the secondary sexual organs become larger, and 

 the libido sexualis is increased. Some extracts, such as those 

 of the pars glandularis of the ox, may have the opposite 

 effect — delaying the growth and maturation of the testis and 

 other parts of the genital tract, and lessening sexual activity; 

 the action of such extracts is discussed in the section follow- 

 ing this. 



The most striking effects of implants in male animals were 

 obtained by Smith (1927, 1930) in hypophysectomized rats. 

 The whole genital tract, which prior to treatment was atro- 

 phic, was restored to a normal size and appearance. Not only 

 did the implants bring about normal secretory activity on the 

 part of the interstitial tissue of the testis, but there was also 

 a restoration of spermatogenesis so complete that fertile mat- 

 ings occurred between normal female rats and the hypophy- 

 sectomized males which had received homo-implants. 



THE COMPARATIVE PHYSIOLOGY OF THE GONADOTROPIC 

 HORMONe(s) of the anterior PITUITARY 



The comparative physiology of the gonadotropic hor- 

 mone(s) of the anterior pituitary not only is of scientific in- 

 terest in itself but also is of importance because of the evi- 

 dence it is thought to provide in favor of the existence of sev- 

 eral gonadotropic hormones. Moreover, it is impossible to 

 attempt correctly to evaluate the assay of gonadotropic hor- 

 mone(s) without bearing in mind how different the response 

 of the gonads — both qualitatively and quantitatively — may 

 be in different animals. Frequently it is difficult to say to 

 what extent differences are apparent rather than real. For 

 example, the metabolism of a gonadotropic hormone, admin- 



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