Autoradiographic Localization of Binding Sites for Human Follicle-Stimulating Hormone in Reptilian Testes and Ovaries

Topical autoradiographic analyses allowed localization of sites capable of binding 1 2 5 I-hFSH in reptilian (turtle, snake and lizard) ovaries and testes. Specific binding of 1 2 5 I-hFSH (determined in the presence and absence of an excess of unlabeled hFSH) was observed to both intratubular and interstitial elements in the reptilian testes. Particularly striking in this regard was the intense binding to the circumtesticular Leydig cell capsule in the lizard Cnemidophorus . In ovaries, binding was localized to the epithelial layer surrounding follicles, to the granulosa cell layer and theca interna of the follicle wall and to the vitelline membrane of the oocyte.