CYP7B1, a cytochrome P450 enzyme, metabolizes several steroids involved in hormonal signaling including 5a-androstane-3b,17b-diol (3b-Adiol), an estrogen receptor agonist, and dehydroepiandrosterone, a precursor for sex hormones. Previous studies have suggested that CYP7B1-dependent metab-olism involving dehydroepiandrosterone or 3b-Adiol may play an impor-tant role for estrogen receptor b-mediated signaling.