Oxidoreductase with a preference for NAD. Oxidizes all-trans-retinol, 9-cis-retinol, 11-cis-retinol and 13-cis-retinol to the corresponding aldehydes ( ). Has higher activity towards CRBP-bound retinol than with free retinol . Oxidizes also 3-alpha-hydroxysteroids. Oxidizes androstanediol and androsterone to dihydrotestosterone and androstanedione. Can also catalyze the reverse reaction ( ).
Subcellular locations: Microsome membrane, Endoplasmic reticulum membrane
Highly expressed in adult liver (at protein level) . Detected in endometrium, liver and foreskin (, ). Detected in the spineous layers of adult skin, and at lower levels in basal and granular skin layers . Detected in fetal liver and lung.