EFFECTS OF CASTRATION AND EXOGENOUS TESTOSTERONE SUPPLEMENTATION IN AN ANIMAL-MODEL OF PENILE ERECTION

The dependence of erectile behavior on androgen functioning is well es tablished. Castration produces loss of both libido and potency in man and animals. The present study, using an animal model for potency, dem onstrates the dependence of centrally induced erectile behavior on an intact androgen milieu. Castrated rats failed to produce an erection i n response to apomorphine, an agent shown to produce erection in nearl y all normal rats. Administration of exogenous testosterone propionate in dosages exceeding 60 mu g./kg. produced a significant increase in erectile behavior. Yawning, an essentially parallel phenomenon to the stimulation of the erectile response, was also decreased following cas tration and responded similarly to increasing amounts of exogenous tes tosterone, demonstrating the influence of androgen functioning on the central nervous system. It was concluded that testosterone is a necess ary prerequisite for the maintenance of a centrally induced erectile a nd yawning response. In an animal model of penile erection, testostero ne increases the number of erections in a dose-dependent manner in cas trated rats. The dependence of the erectile response on testosterone i s, at least in part, centrally mediated.