INSULIN INHIBITS CHANGES IN THE PHOSPHOLIPID PROFILES IN SCIATIC-NERVES FROM STREPTOZOCIN-INDUCED DIABETIC RATS - A P-31 MAGNETIC-RESONANCESTUDY

Sciatic nerve phospholipids obtained from insulin-treated streptozocin -induced diabetic, nontreated streptozocin-induced diabetic, and healt hy, control male Sprague-Dawley rats after eighteen weeks of diabetes were studied by P-31 NMR spectrometry. Eleven phospholipids resonances were identified as follows: Phosphatidic acid (Chemical shift, 0.30 p pm), dihydrosphingomyelin (0.13 ppm), ethanolamine plasmalogen (0.07 p pm), phosphatidylethanolamine (0.03 ppm), phosphatidylserine (-0.05 pp m), sphingomyelin (-0.09 ppm), lysophosphatidylcholine (-0.28 ppm), ph osphatidylinositol (-0.30 ppm), alkylacylglycerophosphorylcholine (-0. 78 ppm), choline plasmalogen (-0.80 ppm), and phosphatidylcholine (-0. 84 ppm). Diabetic rats showed that phosphatidylcholine was significant ly elevated (P < 0.05), and ethanolamine plasmalogen. and choline plas malogen were significantly lower when compared with both control and i nsulin treated rats. The choline ratio (choline-containing phospholipi ds over noncholine phospholipids) was significantly elevated in the di abetic group, when compared with both control and insulin-treated grou ps. The ethanolamine ratio (ethanolamine-containing phospholipids over nonethanolamine phospholipids) and the ratio of the ethanolamine rati o over the choline ratio, was significantly elevated in the control an d the insulin-treated groups when compared with the diabetic group. Th e presence of phosphatidic acid and the significance in phosphatidylch oline and ethanolamine plasmalogen, suggested that insulin had a role in the phosphatidylcholine metabolism in the rat nerve.