Direct Measurement of Polyol Pathway Activity in the Ocular Lens

A method to measure the polyol pathway metabolic flux in the intact rabbit lens by ¹³C nuclear magnetic resonance spectroscopy is described. In the lens exposed to 35.5 mM glucose, the polyol pathway accounts for ⅓ of the total glucose turnover. The high metabolic activity of the pathway suggests a significant alteration in the reduced to oxidized pyridine nucleotide ratio in the lens exposed to high glucose.