Figure 1.

Diagram showing the endocrine pathway where 3βAdiol and ERβ regulate prostate growth. In this pathway, DHT is derived from testosterone through the action of 5α-reductase, and 3βAdiol is derived from DHT through the activity of the enzyme 3β-hydroxysteroid dehydrogenase (3βHSD). On binding to ERβ, 3βAdiol represses the expression of androgen receptor (AR) and, therefore, inhibits androgen-driven proliferation. The levels of 3βAdiol in the prostate are regulated by the expression of CYP7B1, which inactivates 3βAdiol by converting it to 5α-androstane-3β,6α,17β-triol and to 5α-androstane-3β,7α,17β-triol (6α and 7α triols).