HSD17b6 has both oxidoreductase and epimerase activities and is involved in androgen catabolism. The oxidoreductase activity can convert 3 alpha-adiol to dihydrotestosterone, while the epimerase activity can convert androsterone to epi-androsterone. Both reactions use NAD+ as the preferred cofactor. This gene is a member of the retinol dehydrogenase family. Transcript variants utilizing alternative polyadenylation signals exist.Detected in liver and prostate (at protein level). Detected in adult liver, lung, brain, placenta, prostate, adrenal gland, testis, mammary gland, spleen, spinal cord and uterus. Detected in caudate nucleus, and at lower levels in amygdala, corpus callosum, hippocampus, substantia nigra and thalamus. Detected in fetal lung, liver and brain.