[Role of androgen in the elderly. Male sexual dysfunction and androgen]

Testosterone enhances DA release in the MPOA at rest and with sexual challenge, possibly by upregulating NOS, which increases NO and thereby increases DA release. Androgens have beneficial effects on endothelial cells and smooth-muscle cells. Testosterone and dihydrotestosterone may also relax penile artery and cavernous smooth muscle through their nongenomic effects. In rats, castration has been reported to decrease arterial flow, induce venous leakage, and reduce the erectile response to stimulation of the cavernous nerve. Hypogonadal patients in whom PDE5 inhibitor failed could be rescued by the administration of testosterone.