Dihydrotestosterone - Effects On Sexual Development

Effects On Sexual Development

In men, approximately 5% of testosterone undergoes 5α-reduction to form the more potent androgen, dihydrotestosterone. DHT has approximately three times greater affinity for androgen receptors than testosterone and has 15-30 times greater affinity than adrenal androgens. During embryogenesis DHT has an essential role in the formation of the male external genitalia, while in the adult DHT acts as the primary androgen in the prostate and in hair follicles.

An example illustrating the significance of DHT for the development of secondary sex characteristics is congenital 5-α-reductase (5-AR) deficiency. This gene lesion can result in pseudohermaphroditism. This condition typically presents with underdeveloped male genitalia and prostate. These individuals are often raised as girls due to their lack of conspicuous male genitalia. In the onset of puberty, although their DHT levels remain very low, their testosterone levels elevate normally. Their musculature develops like that of other male adults. After puberty, men with this condition have a large deficiency of pubic and body hair, and no incidence of male pattern baldness.

Unlike other androgens such as testosterone, DHT cannot be converted by the enzyme aromatase to estradiol. Therefore, it is frequently used in research settings to distinguish between the effects of testosterone caused by binding to the androgen receptor and those caused by testosterone's conversion to estradiol and subsequent binding to estrogen receptors.