EFFECT OF PROPIONYL-L-CARNITINE ON OSCILLATORY POTENTIALS IN ELECTRORETINOGRAM IN STREPTOZOTOCIN-DIABETIC RATS

The effect of propionyl-L-carnitine, an analogue of L-carnitine, and i nsulin on the oscillatory potentials of the electroretinogram was dete rmined in rats with streptozotocin-induced diabetes. Propionyl-L-carni tine was administered at a daily dose of 0.5 g/kg by gavage for 4 week s, while other rats were treated with subcutaneous injections of insul in (8-10 U/day). Both treatments shortened the peak latencies of the o scillatory potentials in the electroretinogram, which were significant ly prolonged in untreated diabetic rats (O-1, O-2 and O-3, and Sigma(O -1 + O-2 + O-3)) (P < 0.0001 vs. untreated normal rats). A significant decrease in the erythrocyte free carnitine level in diabetic rats was prevented by both treatments. Insulin produced a significant reductio n of retinal glucose, sorbitol and fructose levels in diabetic rats, w hile propionyl-L-carnitine failed to do so. However, both treatments m arkedly reduced serum lipids levels in the diabetic rats. These findin gs provide information on the pathogenesis of diabetic retinopathy as well as suggesting the potential therapeutic value of propionyl-L-carn itine for retinopathy.