Androgen receptor the development and maintenance of the male sexual phenotype. In some cell types, testosterone interacts directly with androgen receptors, whereas, in others, testosterone is converted by 5-alpha-reductase to dihydrotestosterone, an even more potent agonist for androgen receptor activation. Testosterone appears to be the primary androgen receptor-activating hormone in the Wolffian duct, whereas dihydrotestosterone is the main androgenic hormone in the urogenital sinus, urogenital tubercle, and hair follicles. Hence, testosterone is responsible primarily for the development of male primary sexual characteristics, whereas dihydrotestosterone is responsible for secondary male characteristics. Androgens cause slow epiphysis, or maturation of the bones, but more of
Transgender hormone therapy (male-to-female) voice deepens in pitch and becomes more resonant. These changes are permanent and are not affected by HRT. Voice therapy and/or surgery may be used instead to achieve a more female-sounding voice. Facial hair develops during puberty and is only slightly affected by HRT. It may, however, be eliminated nearly permanently with laser hair removal, or permanently with electrolysis. The psychological effects of feminizing hormone therapy are harder to define than physical changes. Because hormone therapy is usually the first physical step taken to transition, the act of beginning it has a significant psychological effect, which is difficult to distinguish