GONADOTROPIC SUBSTANCES 



stimulated Leydig's cells much more effectively than did 

 anterior pituitary extract. According to Leonard (1932) the 

 dose, in rat-units, of anterior pituitary extract causing 

 ovulation in the rabbit is much less than the dose of prolan 

 also evaluated in rat-units. Mahnert (1933) found prolan 

 relatively less effective, but he injected what appear to be 

 excessive doses of both prolan and anterior-lobe extract. 

 Hill, Parkes, and White (1934) obtained perhaps different 

 curves of response (see Figs. 23 ^^<^ 41) when they produced 

 ovulation by injecting prolan or anterior pituitary extract. 



The effects of prolan and of anterior pituitary extract 

 have been compared in male and female immature monkeys 

 (M. mulatto) by Engle (1932, I933)- I^ males, prolan more 

 effectively stimulated the interstitial cells of the testis. 

 In females, anterior pituitary extract, unlike prolan, brought 

 about follicular growth in the ovaries, and reddening and 

 edema of the sexual skin; prolan caused atresia of the graafian 

 follicles and luteinization of the theca (see Fig. 36). 



All investigators agree that prolan causes no hypertrophy 

 of the gonads of immature (or mature) male and female birds; 

 it may, indeed, have the opposite effect. On the other hand, 

 anterior pituitary extracts do "stimulate" or otherwise affect 

 the gonads of the fowl, the duck, and the pigeon.'' 



Analogous or different effects following the administration of 

 prolan to hypophysectomized animals. — The administration of 

 prolan to hypophysectomized animals has been found not to 

 bring about functional and anatomical repair of the de- 

 generated or degenerating gonads except in one instance — the 

 hypophysectomized adult male rat. The administration of 

 anterior pituitary implants or extract, on the contrary, may 

 restore the gonads to an apparently normal condition. These 



" See the articles by Noether (1930); Riddle, and Riddle and Polhemus (1931); 

 Calvet (1932); Dingemanse and Kober, Leonard, Pompen and others, Reiss and 

 others, and Schockaert (1933); Evans and Simpson, Hamburger, and Martins 

 (1934); Bates, Lahr, and Riddle (1935). 



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