Abstract
Gonadotrophic extracts of normal [male] urine prepared by tannic acid precipitation restored and maintained spermatogenesis in hypophysectomized rats. This material caused a definite increase in testis wt. in the hypophysectomized immature rat. An increase in seminal vesicle weight was obtained in some instances, indicating the presence of a small amt. of interstitial tissue stimulating factor. Hence [male] urine gonadotrophin acts like similarly prepared extracts of castrate or postmenopausal urine giving predominantly a gametogenic effect.