The role of testosterone in erectile function and dysfunction

Erectile response is centrally and peripherally regulated by androgens. Severe hypogonadism in men usually results in loss of libido and potency which can be restored by androgen administration.It was originally thought that androgens exert their effects on libido and that effects on erections were secondary to effects on libido. It is now clear that androgens are necessary for the maintenance of the anatomical and physiological substrate of erections. Restoring testosterone levels to normal is required in cases of erectile dysfunction.It was long assumed that sexual functions required androgen levels below or at the low end of reference values of testosterone. It is now clear that there are individual differences while the threshold increases with aging.The administration of PDE-5-inhibitors is not always sufficient to restore erectile potency in men, and administration of testosterone improves the therapeutic response to PDE-5-inhibitors considerably.Erectile dysfunction is strongly age-related, and it is evident that its etiology is multi-factorial. It is intriguing that testosterone is interrelated with a number of etiological factors such as obesity, diabetes mellitus and atherosclerosis.