A Potential Role for Aldose Reductase in Steroid Metabolism

Aldose reductase (ALR2) is a monomeric NADPH-dependent reductase distinguished from other members of the aldo-keto reductase enzyme family in its ability to catalyze the reduction of a variety of hexoses and pentoses. The role of ALR2 in enhanced polyol synthesis in diabetic and galactosemic tissues is well documented (Kinoshita and Nishimura, 1988), as is the potential therapeutic use of ALR2 inhibitors to delay or prevent the onset and progression of metabolic complications leading to cataract and retinopathy (Sarges and Oates, 1993). New insights into the structure of ALR2, together with emerging data demonstrating that many individual aldo-keto reductases may participate in divergent metabolic pathways, lead us to question whether sugars represent the only physiologically-relevant substrate of this enzyme.