Hypothalamic control of the hypophyseal gonadotropic function in the adult male green frog, Rana esculenta L.

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Abstract
Removal of the pars distalis, homoiotopic and ectopic autografting of the pars distalis, and transection of the hypothalamo‐hypophyseal link was done and their effect upon the cytology of the pars distalis and its gonadotropic functions was studied in the male green frog, Rana esculenta. Removal of pars distalis led to the regression of gonads and secondary sex organs. The gonadotropic activity of the pars distalis regrafted under the median eminence was comparable to that of the sham‐operated control except that in the gland oriented at an angle of 180° the thumb pads were involuted. The normal functional activity of the regrafted gland can be explained by the contact re‐established between the grafted gland and the portal vessels at the level of the median eminence as ascertained by injections of India ink. The ectopic pars distalis graft showed a general cytological disorganization and regression of the various cell types and its gonadotropic function appeared to be extremely poor. Transection of the hypothalamo‐hypophyseal connections diminished the gonadotropic effectiveness of the pars distalis.