OXYGEN-CONSUMPTION AND ATPASE ACTIVITY IN THE CORNEAL EPITHELIUM OF RABBITS WITH ALLOXAN-INDUCED HYPERGLYCEMIA

Purpose: To more fully investigate the effect of hyperglycemia on the aerobic metabolism of the corneal epithelium. Methods: Corneal epithel ial oxygen uptake rates and adenosine triphosphatase (ATPase) activiti es were measured in alloxan-induced diabetic and control rabbits over a 10 week period. Results: A transient reduction in epithelial oxygen uptake rate was seen at week 1. A chronic 14% reduction in oxygen cons umption occurred after 6 weeks of hyperglycemia. Epithelial ouabain-se nsitive ATPase activity was unaffected by 10 weeks of hyperglycemia. E pithelial ouabain-insensitive ATPase activity decreased 14% after 10 w eeks of hyperglycemia. Conclusions: Ten weeks of hyperglycemia in the alloxan induced diabetic rabbit was associated with a 14% decrease in corneal oxygen uptake, a 14% decrease in corneal epithelial ouabain-in sensitive ATPase activity and no change in corneal epithelial ouabain- sensitive ATPase activity. The Crabtree effect may help explain some o f the clinical signs seen in the diabetic cornea as well as explaining why diabetic patients can wear contact lenses with minimal clinical p roblems.