Long-term endocrine responses to vasectomy in the adult rat

Groups of mature rats were vasectomized or sham-operated for subsequent study 18 months later in order to assess the possible chronic consequences of vasectomy. Organ weights were recorded and circulating levels of both testosterone and corticosterone were determined. Endocrine function of the testis was evaluated by the measurement of testosterone and androstenedione in testicular venous blood. Vasectomy gave rise to a high incidence (7 in 8) of bilateral granuloma formation of the vas deferens which varied in size. There occurred a lower incidence (1 in 8) of unilateral cysts of the epididymis. Adrenal gland weight and circulating corticosterone in vasectomized animals were lower than control values, but not significantly so. Vasectomy led to decline in testis weight and endocrine function as witnessed by a marked depression of the levels of androstenedione and, in particular, of testosterone. A significant lowering of the weight of the ventral prostate in vasectomized rats was not paralleled by a similar change in circulating testosterone. Levels of the latter were extremely low in both experimental and control groups of rats.