Metformin treatment of angiotensin II‐hypertensive rat decreases phenylephrine‐mediated increased contraction in pudendal arteries

Abstract

Hypertension is a major risk factor for erectile dysfunction (ED). Increased circulating angiotensin II (AngII) levels are associated with ED. Data from our laboratory showed that AngII infusion resulted in increased corpus cavernosum (CC) contractility, resulting in ED. Metformin treatment restored normal CC tone and erectile function in AngII‐infused rats. Pudendal artery (PA), the major artery providing blood flow to the penis, is important for normal erectile function. This study tested the hypothesis that AngII infusion will result in increased PA contractility, thus limiting blood flow to penis, and that metformin treatment will restore normal PA contractility. Male Sprague‐Dawley rats were implanted with mini‐osmotic pumps containing saline or AngII (70 ng/min, 28 days). Animals were then treated with metformin (500mg/Kg/day) or vehicle during the last week of AngII infusion. AngII infused rats displayed ED which was associated with increased phenylephrine‐mediated contraction in PA (% of the U‐46619 contraction) (Emax= 400.7% ± 14.47 in AngII vs Emax= 208.6% ± 7.79 in sham). Metformin treatment restored erectile function in AngII infused animals, and reversed the AngII‐mediated increase in PA contractility (Emax= 277.2% ± 14.55 in AngII+metformin vs Emax= 400.7% ± 14.47 in AngII). We conclude that metfromin treatment may be beneficial to restore normal erectile function.