EFFECT OF PROPIONYL-L-CARNITINE TREATMENT ON MEMBRANE PHOSPHOLIPID FATTY-ACID TURNOVER IN DIABETIC RAT ERYTHROCYTES

In this work we have examined the effect of the oral administration of propionyl-l-carnitine (PLC) on the membrane phospholipid fatty acid t urnover of erythrocytes from streptozotocin-induced diabetic rats. A s tatistically significant reduction in radioactive palmitate, oleate, a nd linoleate, but not arachidonate, incorporation into membrane phosph atidylcholine (PC) of diabetic rat erythrocytes with respect to contro l animals was found. Changes in radioactive fatty acid incorporation w ere also found in diabetic red cell phosphatidylethanolamine (PE), tho ugh they were not statistically significant. Oral propionyl-L-carnitin e (PLC) treatment of diabetic rats partially restored the ability of i ntact red cells to reacylate membrane PC with palmitate and oleate, an d reacylation with linoleate was fully restored. The analysis of the m embrane phospholipid fatty acid composition revealed a consistent incr ease of linoleate levels in diabetic rat red cells, and a modest decre ase of palmitate, oleate and arachidonate. The phospholipid fatty acid composition of diabetic red blood cells was not affected by the PLC t reatment. Lysophosphatidylcholine acyl-CoA transferase (LAT) specific activity measured with either palmitoyl-CoA or oleyl-CoA was significa ntly reduced in diabetic erythrocyte membranes in comparison to contro ls. In addition, LAT kinetic parameters of diabetic erythrocytes were altered. The reduced LAT activity could be partially corrected by PLC treatment of diabetic rats. Our data suggest that the impaired erythro cyte membrane physiological expression induced by the diabetic disease may be attenuated by the beneficial activity of PLC on the red cell m embrane phospholipid fatty acid turnover.