Besides being a 3-alpha-hydroxysteroid dehydrogenase, the enzyme can accomplish diverse functions: as quinone reductase, as an aromatic alcohol dehydrogenase, as dihydrodiol dehydrogenase, and as 9-, 11-, and 15-hydroxyprostaglandin dehydrogenase. a 3alpha-hydroxysteroid + NADP(+) = a 3-oxosteroid + H(+) + NADPH a 3alpha-hydroxysteroid + NAD(+) = a 3-oxosteroid + H(+) + NADH Potently inhibited by the nonsteroidal anti-inflammatory drugs (NSAID). Monomer. In brain, highest levels found in olfactory bulb. Moderate levels present in cerebellum, cerebral cortex, hypothalamus and pituitary. Low levels present in amygdala, brain stem, caudate putamen, cingulate cortex, hippocampus, midbrain, and thalamus. Belongs to the aldo/keto reductase family.