Endothelin-1 in Diabetic and Nondiabetic Men With Erectile Dysfunction

PURPOSE: We evaluated plasma concentration of endothelin-1 in diabetic and nondiabetic men complaining of erectile dysfunction, and the variation of endothelin-1 in cavernous body blood during intracavernous injection of prostaglandin E1. MATERIALS AND METHODS: We evaluated plasma concentrations of endothelin-1 in venous blood of 20 men with erectile dysfunction, 10 with and 10 without diabetes. Plasma concentration of endothelin-1 was also evaluated in the cavernous body blood of the 20 men with erectile dysfunction, during erection induced by intracavernous injection of 10 micrograms prostaglandin E1. A severe vasculogenic component of erectile dysfunction was excluded in all patients. RESULTS: Basal plasma concentration of endothelin-1 in the cubital vein was increased in nondiabetic (1.13 +/- 0.4 pg./ml.) and in diabetic (1.80 +/- 0.2 pg./ml.) patients with erectile dysfunction, compared to control men (0.64 +/- 0.1 pg./ml.) (p < 0.0005 and p < 0.0001, respectively), and in diabetic compared with nondiabetic patients (p < 0.002). No difference and close correlation were observed in the concentration of endothelin-1 in the cavernous body blood evaluated 5 minutes and 30 minutes after injection of prostaglandin E1 (r = 0.89, p < 0.0001, y = 0.98 x + -0.066). The concentration of endothelin-1 in the cavernous body blood evaluated 30 minutes after injection of prostaglandin E1 did not show any difference compared to peripheral venous concentration of the peptide in the 2 patient groups. Concentrations of endothelin-1 in the peripheral vein and the cavernous body blood were not different in patients with a full erection compared with incomplete penis erection after injection of prostaglandin E1 in the cavernous body.