Effect of Low Androgen Status on the Expression of P2Y Receptors in the Corpus Cavernosum of Rats.

OBJECTIVE: To determine whether low androgen status impacts erectile function by regulating the expression of the G protein-coupled P2Y receptors (P2Y1, P2Y2, P2Y4, and P2Y6) in the corpus cavernosum penis of rats.

MATERIALS AND METHODS: A total of 36 healthy, 8-week-old, male Sprague-Dawley rats were randomly allocated into 6 groups: 4 weeks of androgen replacement therapy post castration (group A); 4 weeks post castration (group B); 4 weeks post sham operation (group C); 8 weeks of androgen replacement therapy post castration (group D); 8 weeks post castration (group E); and 8 weeks post sham operation (group F). The ratio of maximum intracavernous pressure/mean arterial pressure was measured for every group and detected the expression of P2Y1, P2Y2, P2Y4, and P2Y6 in the rat corpus cavernosum penis of every group.

RESULTS: The ratio of maximum intracavernous pressure/mean arterial pressure significantly declined in the castration group compared with the control group (P <.01). The expression of P2Y1, P2Y2, P2Y4, and P2Y6 and the ratio of the phosphorylated endothelial nitric oxide synthase (eNOS)/eNOS proteins were significantly lower in the castration group vs treatment or control (P <.01) whereas they were significantly lower in the group of 8 weeks vs 4 weeks post castration (P <.05). The rat serum testosterone levels in every group were positively correlated with the protein levels of P2Y1, P2Y2, P2Y4, and P2Y6.

CONCLUSION: Downregulation of the expression of the P2Y1, P2Y2, P2Y4, and P2Y6 receptors that reduces the ratio of phosphorylated eNOS/eNOS and eNOS activity may be one of the important mechanisms of erectile dysfunction caused by low androgen status.