Activities of NADPH-dependent reductases and sorbitol dehydrogenase in canine and feline lenses

Abstract

Objective - To measure activities of NADPH-dependent reductases and sorbitol dehydrogenase in lenses from healthy dogs and cats. Sample Population - Lenses from 37 dogs and 23 cats. All animals were healthy and had serum glucose concentrations within reference limits. Procedure - Lenses were homogenized, and activities of NADPH-dependent reductases and sorbitol dehydrogenase were measured spectrophotometrically. Results - Activities of NADPH-dependent reductases and sorbitol dehydrogenase were significantly lower in lenses from cats than in lenses from dogs. However, the ratio of NADPH-dependent reductases activity-to-sorbitol dehydrogenase activity was significantly higher in lenses from cats than in lenses from dogs. Conclusions and Clinical Relevance - Results indicate that during periods of hyperglycemia, sorbitol would accumulate at a faster rate in the lenses of cats than in the lenses of dogs. Thus, the higher incidence of diabetic cataracts in dogs, compared with cats, is likely not attributable to a difference in the ratio of NADPH-dependent reductases activity-to-sorbitol dehydrogenase activity.