NADPH-dependent oxidoreductase which catalyzes the reduction of a variety of compounds bearing carbonyl groups including steroids, retinoids and xenobiotics (PubMed:24246760, PubMed:26466768, PubMed:28457967, PubMed:28687384). Catalyzes the reduction/inactivation of 5alpha-dihydrotestosterone to 3alpha-androstanediol, with a possible role in the modulation of androgen receptor function (PubMed:28457967, PubMed:28687384). Involved in the reduction of all-trans-retinal to all-trans-retinol (PubMed:26466768). Converts cortisone to 20beta-dihydrocortisone in vitro, although the physiological relevance of this activity is questionable (PubMed:28457967). Reduces exogenous compounds such as quinones (1,2-naphtoquinone, 9,10-phenantrenequinone and benzoquinone) and other xenobiotics (alpha-diketones) in vitro, suggesting a role in the biotransformation of xenobiotics with carbonyl group (PubMed:24246760, PubMed:26466768). A dehydrogenase activity has not been detected so far (PubMed:24246760). May play a role as tumor suppressor (PubMed:26311046).
