Conflicting reports based upon the indirect effects of vasectomy on plasma testosterone levels of the rat have recently been published. Sackler et al. (1973) reported decreased urinary ketosteroids and testicular weight after vasectomy of immature rats. Thakur et al. ( 1972 ) studied the fructose levels in the coagulating gland and maltase activity in the dorsolateral prostate gland in the mature rat after vasectomy and concluded that testosterone secretion increased.