Effect of aldosterone on isolated human penile corpus cavernosum tissue

Abstract

To clarify the physiological effects of aldosterone on human penile corpus cavernosum (hPCC) tissue, as aldosterone has a wider physiological action than just the maintenance of electrolyte balance, and there are mineralocorticoid receptors, i.e. aldosterone receptors, in hPCC tissue. Specimens of hPCC were obtained from 10 patients (mean age 38 years, range 21-75), with informed consent and approval by the local ethics committee. One patient had a penectomy because of penile cancer, and nine had a penile biopsy because of erectile dysfunction. Patients with diabetes mellitus, hypertension or ischaemic heart disease were excluded. In a pharmacological study we evaluated the effect of aldosterone on the isolated hPCC tissues. Aldosterone caused no significant change in resting tension and did not affect the nitric oxide-dependent relaxation reaction. However, the dose-response curve of noradrenaline was shifted to the left when the strip preparation was treated with aldosterone (1 x 10(-5)M) for 20 min before administering noradrenaline. Moreover, the shift to the left was completely blocked when spironolactone (anti-aldosterone agent) was added as a pre-treatment. Pre-treatment with aldosterone also significantly extended the mean (SEM) time required to reach 50% relaxation of a noradrenaline-induced contraction, of 9.3 (1.5) min, vs the control, of 5.2 (1.0) min (P = 0.002). Aldosterone has no direct contractile action or a relaxant action on human penile cavernous tissue, but acts to significantly enhance the noradrenaline-induced contraction. The effect on the noradrenaline-induced contraction is probably caused by aldosterone enhancing the affinity of the alpha-receptors for noradrenaline in hPCC. We suggest that aldosterone acts to enhance contraction of hPCC tissue, and is one of the restraining factors for human penile erection.