Catalyzes the NADPH-dependent reduction of several pentoses, tetroses, trioses, alpha-dicarbonyl compounds and L-xylulose. Participates in the uronate cycle of glucose metabolism. May play a role in the water absorption and cellular osmoregulation in the proximal renal tubules by producing xylitol, an osmolyte, thereby preventing osmolytic stress from occurring in the renal tubules. NADP(+) + xylitol = H(+) + L-xylulose + NADPH Homotetramer. Probably recruited to membranes via an interaction with phosphatidylinositol. During epididymal transit, it accumulates on the acrosomal cap of spermatozoa. Highly expressed in kidney and liver. Expressed in epididymis. Weakly expressed in brain, heart, lung, spleen and testis. Belongs to the short-chain dehydrogenases/reductases (SDR) family.