Antihypertensive drugs induce structural remodeling of the penile vasculature

Purpose: There is a strong association between hypertension and erectile dy sfunction. Studies of the treatment of hypertension have shown that some ph armacological agents are capable of inducing regression of the vascular str ucture during treatment. We determined whether penile vascular structure is as susceptible as other vascular beds to regression during antihypertensiv e drug treatment. Materials and Methods: Adult spontaneously hypertensive rats were treated f or 1 or 2 weeks with 30 mg./kg. enalapril daily, or for 2 weeks with 45 mg. /kg. hydralazine daily. Structurally based vascular resistance was determin ed in isolated penile and skeletal muscle vascular beds perfused with Tyrod e-dextran. A cumulative alpha1-adrenoceptor concentration constrictor respo nse curve to 1 to 100 mug./ml. methoxamine was constructed and the maximum constrictor response (vasopressin, methoxamine and angiotensin II) indicati ng the tissue yield point (that is the average medial bulk of vascular smoo th muscle) was determined. The hearts were excised and the ventricles were separated and weighed. Results: Enalapril treatment progressively regressed cardiac and vascular s tructure during the 1 and 2-week treatment periods with a mean tissue yield point plus or minus standard deviation of -5.91% +/- 5.1% (p <0.05) and -1 2.1% +/- 6.0% (p <0.05), and a mean left ventricle mass of -11.8% +/- 2.2% (p <0.05) and -13.6% +/- 3.2% (p <0.05), respectively. Hydralazine treatmen t for 2 weeks was less effective on vascular regression with a mean yield o f -7.3% +/- 2.9% (p <0.05) and it did not alter left ventricle hypertrophy compared with controls (3.7% +/- 5.0%). Conclusions: The data suggest that renin-angiotensin system inhibition may at least partially normalize penile vascular structure. The impact of these changes on erectile function must be determined.