THE GONADOTROPIC HORMONES 



corpus luteum formation may result from the injection of 

 dehydroandrosterone or testosterone into rats. Obviously 

 suppression of oestrus by an androgen might be related to 

 such an action. There is no evidence that the anterior pitui- 

 tary plays an important part in these effects of androgens. 

 It has been suggested that the ovary may convert an andro- 

 gen into an oestrogen. 



There is good evidence from recently published reports that 

 androgenic substances also directly affect the testes." Wells 

 and Moore (1936) found that androsterone or extract of male 

 urine or bull testis (like gonadotropic extracts) might cause 

 precocious spermatogenesis in the ground squirrel iCitellus 

 tridecemlineatus) weeks or months before the germinal epi- 

 thelium normally becomes active. None of their animals was 

 hypophysectomized. Confirming the work of Walsh, Cuyler, 

 and McCullagh, Nelson and Gallagher (1936) as well as 

 Nelson and Merckel (1937) concluded that "male hormone" 

 (extract of urine, crystalline androgens) maintains spermato- 

 genesis in the hypophysectomized rat.^^ Injection must be 

 started a day or two after hypophysectomy; if there is an in- 

 terval of 3 weeks between hypophysectomy and initiation of 

 treatment, spermatogenesis cannot be initiated perhaps be- 

 cause of irreparable damage to the germinal epithelium. The 

 treatment does not correct the degenerative changes in the 

 interstitial cells. Cutuly, McCullagh, and Cutuly (1937) be- 

 lieved that the maintenance of scrotal function accounted for 

 the favorable action of androgens on spermatogenesis; how- 

 ever, Nelson and Merckel pointed out that scrotal function 



5' For studies comparing the effect of several androgens on the secondary sexual 

 organs of normal and hypophysectomized male rats, see Freud (1935) and Laqueur, 

 Dingemanse, and Freud (1935). For example, although (with a cosubstance) testos- 

 terone and dihydroandrosterone might produce typical responses in hypophy- 

 sectomized animals, androsterone was almost without action. 



5^ McEuen, Selye, and Collip (1937) concluded that normal testicular structure 

 in the hypophysectomized rat is not maintained by the injection of testosterone. 

 Cutuly, McCullagh, and Cutuly (1937) prevented testicular atrophy in hypophy- 

 sectomized rats by androsterone (1.50 mg. daily) and testosterone (0.45-1.50 mg. 

 daily) but not by dihydroandrosterone benzoate (1.25 mg. daily). 



[93] 



