The effects of testosterone on the cavernous tissue and erectile function
A review of the current literature is conducted to explore the developmental aspects, animal and human experiences and the effects of pharmacological manipulation to explain the role androgens play in sexual function with special emphasis on erectile function and the erectile tissue. This review reveals that androgens are necessary for the normal development of the penis and their deficiency results in significant structural abnormalities. Although androgen receptors in the penis decrease after puberty, they usually do not disappear completely. Animal data show that androgens support erectile function through a direct effect on the erectile tissue. Experimental castration results in impaired erectile response to central and peripheral stimulation and decrease in penile tissue concentration of nitric oxide synthase-containing nerves. Testosterone replacement reverses these abnormalities. In the rat penis, apoptosis is induced by castration and new DNA synthesis is induced by testosterone replenishment. Human data are less clear than animal data. Castration results in loss of libido and in erectile dysfunction. However, these effects are not universal. Testosterone enhances libido, frequency of sexual acts and sleep-related erections. Its effects on erotic erections are not clear.