It has been reported that exogenous serotonin can interfere with both testicular exocrine and endocrine functions of the adult male rat (Boccabella, Salgado & Alger, 1962). These investigators postulated that the lesions may have resulted from testicular ischaemia since a vasodilator prevented the appearance of pycnotic primary spermatocytes and multinucleated spermatids induced by exogenous serotonin. More recently, Eccleston, Thoa & Axelrod (1968) have investigated the marked accumulation in vitro of [14C]serotonin in guinea-pig ductus deferens. Previously, Taxi & Droz (1966) injected the serotonin precursor [3H]5-hydroxytryptophan and demonstrated autoradiographically that the indoleamine accumulated in the sympathetic neurons of the rat ductus deferens.
The present study concerns the relative affinities in vitro of male rat reproductive tract tissues and kidney