**2.1 Disparate effects and mechanisms of androgens may be meaningful**

Androgens have profound effects on physiological and psychological function. This is apparent throughout the lifespan and with normal development as well as in pathological situations. In early development, androgens lay the framework for sex differences in reproductive tissues and brain circuitry and behavior. At puberty, typical diurnal secretion of androgens in males is initiated. The main circulating androgen is T, which can be aromatized into estradiol and 5α-reduced to dihydrotestosterone (DHT). DHT is further converted to 5α-androstane,3α,17β-diol (3α-diol) by 3α-hydroxysteroid dehydrogenase. These different androgens have varied effects and mechanisms that will be discussed throughout this paper (**Figure 2**).
