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. Highly expressed in kidney, liver and epididymis. In the epididymis, it is mainly expressed in the proximal and distal sections of the corpus region. Weakly or not expressed in brain, lung, heart, spleen and testis. The disease is caused by variants affecting the gene represented in this entry. Belongs to the short-chain dehydrogenases/reductases (SDR) family.