Further studies on 20 beta-hydroxysteroid dehydrogenase with carbonyl reductase-like activity present in liver microsomes of male rats

Further characterizations of 20 beta-hydroxysteroid dehydrogenase (20 beta- HSD) present in liver microsomes of male rats were examined. A significant relationship was observed between 20 beta-HSD and acetohexamide reductase ( AHR) activities in liver microsomes of male rats. The hepatic microsomal 20 beta-HSD and AHR preferentially required NADPH as a cofactor. When NADPH w as replaced by NADH, NADP or NAD at the same concentration, these reductase activities were little detected. The hepatic microsomal 20 beta-HSD and AH R activities in streptozotocin-induced diabetic rats were much lower than t hose in the corresponding controls, The hepatic microsomal 20 beta-HSD and AHR activities appeared as one main peak, respectively, on DEAE-Sephacel co lumn chromatography, and the peak of 20 beta-HSD activity was in good agree ment with that of AHR activity. Based on these results, we conclude that 20 beta-HSD present in liver microsomes of male rats functions as AHR, and ex hibits a carbonyl reductase-like activity. (C) 2000 Elsevier Science Inc. A ll rights reserved.