GONADOTROPIC SUBSTANCES 



and did not stimulate spermatogenesis. Brouha and Sim- 

 monet believed that premature spermatogenesis also oc- 

 curred. Numerous subsequent reports support the observa- 

 tions of Engle.^^ Some investigators like Borst, Borst and 

 Gostimirovic (1930), Boeters (1931), and Gostimirovic (1932) 

 believed that particularly the spermatogonia or sperma- 

 tocytes developed more rapidly or were sensitized to more 

 rapid development in immature mice and rats receiving pro- 

 lan. They did not observe true premature spermatogenesis. 

 Practically all other investigators are not convinced that pro- 

 lan has any effect on the germinal epithelium of the immature 

 mouse and rat.'' 



All reports agree that the amount of interstitial tissue in 

 the testis is increased after the injection of prolan into im- 

 mature animals (see Fig. 37). Depending upon the animals' 

 age, the dose, and the duration of treatment, the weight of 

 the testes may be unaltered (or even lighter) or increased. 

 However, testicular hypertrophy is not ordinarily observed 

 in experiments of short duration. The most striking effects 

 are secondary to the stimulation of the interstitial cells. All 

 the accessory sexual organs (seminal vesicles, prostate, bul- 

 bourethral glands, etc.) undergo a hypertrophy which is most 

 clearly and easily observed in the seminal vesicles. The in- 

 jection of prolan into castrated animals is followed by no 

 changes in the accessory organs. For a description of the 

 effects of prolan on the testes of hypophysectomized rats, see 

 page 211. 



Large doses of pregnancy-urine or extracts of pregnancy- 

 urine, particularly if administered over a considerable period, 

 appear to damage or cause degenerative changes in the 



'* For references not mentioned in the text, see: Colombi, De Jongh and Dinge- 

 manse, Laurent (1930); De Jongh, De Jongh and Laqueur, Kunischige (1931); 

 Molien, D'Amour, and Gustavson, Robson and Taylor (1933); Geiger (1934). 



■9 Hertwig (1933) studied spermatogenesis in older rats to which prolan had been 

 administered. Abnormally small spermatids, incapable of transformation into 

 spermatozoa, were formed. 



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