Effect of Intra-Scrotal Implants of Prostaglandin E2 or F2α on Blood Steroids in the Adult Male Rats

The effects of the insertion of Silastic-PVP tubes containing either 3 mg PGF_2α or 3 mg PGE₂ per tube into each of the scrotal sacs on steroid concentration were studied in the mature male rat. Seven days after the insertion a more pronounced reduction in the weights of the testes, ventral prostate and seminal vesicles was recorded in the PGE₂- than in the PGF_2α-treated males. Further, it was observed that 3 and 7 days after the initiation of treatment the serum testosterone concentration significantly decreased ( P < 0.01). Likewise, serum 5α-dihydrotestosterone, androstenedione and progesterone were also reduced significantly. This suggests that a decrease in progesterone synthesis impairs androgen production, which in turn leads to a reduction in the weights of testes, epididymides and accessory glands.