INFLUENCE OF ZINC-DEFICIENCY ON THE CONTENTS OF INDIVIDUAL PHOSPHOLIPIDS AND THEIR FATTY-ACID COMPOSITIONS IN ERYTHROCYTE-MEMBRANES OF FORCED-FED RATS

In the present study the influence of zinc deficiency on the contents of individual phospholipids and their fatty acid compositions in erythrocyte membranes was investigated. Using the forced-feeding technique within seven days severe zinc deficiency was induced which was verified by a reduced plasma zinc concentration (-71%) and by a reduced activity of plasma alkaline phosphatase (-66%). Erythrocyte membranes of zinc deficient animals had higher contents of the phospholipids phosphatidylcholine, diacyl phosphatidylethanolamine, plasmalogen phosphatidylethanolamine, sphingomyelin as well as total phospholipids. Erythrocyte membrane phospholipids of zinc deficient animals had higher contents of long chain n-3 fatty acids, especially of docosahexaenoic acid. Erythrocyte membrane total fatty acids of zinc deficient animals also had a higher double bound index and a higher mean chain length than those of control animals. The largest changes occured in the fatty acid composition of phosphatidylcholin. In this phospholipid the contents of stearic acid, linolic acid, docosapentaenoic acid and docosahexaenoic acid where changed in zinc deficient animals. In zinc deficient animals there were also changes of the composition of plasma fatty acids similar to those in erythrocyte membrane phosphatidylcholine. The observed changes of the contents of phospholipids and their fatty acid compositions in erythrocyte membranes might give an explanations for the increased osmotic fragility of erythrocytes in zinc deficiency. On the other hand, the changes of phospholipid contents and their fatty acid composition in zinc deficiency might be the result of a compensatory mechanism in order to decrease the osmotic fragility which is higher in zinc deficiency.