GONADOTROPIC SUBSTANCES 



1932). This would be expected if prolan actually is a mixture 

 of prolans "A" and "B." Most of the reported effects of pro- 

 lan can be interpreted as the effects of two or possibly more 

 combined prolans; some effects appear to be related to only 

 one of two or more prolans. However, proof of their existence 

 awaits chemical separation. That the most potent prepara- 

 tions yet made produced both follicular maturation and lute- 

 inization may have depended (i) on the method of assay 

 which did not permit the recognition of prolan "B" alone, or 

 (2) on the difficulty of separating substances of similar prop- 

 erties. Considered as a whole, the evidence suggests but does 

 not prove that there is more than one prolan. 



As Aschheim and Zondek emphasized in their first reports, 

 prolan resembles anterior pituitary implants or extracts in its 

 effects on the genital tract of the immature mammal: as a 

 result of its administration, internal secretions peculiar to the 

 ovary or testis are secreted at a faster rate or in greater 

 amount so that secondary "stimulating" effects are produced 

 in the uterus, vagina, seminal vesicles, prostate, etc. On the 

 other hand, the genital tracts of animals deprived of their 

 ovaries or testes are not altered following the administration 

 of prolan. Although most experiments have been performed 

 in mammals, the gonads of animals of other classes are known 

 to respond to prolan. Calvet (1932) found that considerable 

 development of the ovaries could be produced in lampreys 

 {Petromyzon planeri) simply by placing them in a bath con- 

 taining pregnancy-urine. According to Ogilvie (1933) prolan 

 caused ovulation in both the Mexican axolotl and the Jap- 

 anese newt {Triturus pyrrhogaster) . In the toad, Xenopus lae- 

 vis, Bellerby (1934) as well as Shapiro and Zwarenstein (1934) 

 produced ovulation by injecting pregnancy-urine. Similar re- 

 sults were obtained by injecting an extract of pregnancy- 

 urine into the bull frog (Rana catesbiand) and into Fowler's 

 toad (Rugh, 1935). However, in the American toad {Bujo 

 americanus) and in some frogs {R. clamitans^ R. pipiens, and 



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