Effects of a fatty acid deficiency on lipids of whole brain, microsomes, and myelin in the rat

The lipid compositions of whole brain homogenates and microsomal and myelin fractions isolated from the brains of 6-month-old rats raised on a lab chow diet, a fatty acid-deficient diet, and a deficient diet supplemented with 5% (w/w) corn oil were determined. Brain and body weights were significantly lower in the fatty acid-deficient group. The compositions of alk-1-enyl groups and phospholipids of whole brain homogenates of rats maintained on the three diets were not different. However, marked alterations were found in the acyl group compositions of the major phosphoglycerides from whole brain homogenates and from the myelin and microsomal fractions of rats maintained on the fatty acid-deficient diet. With the deficient diet, 20:3(n - 9) was found in the major phosphoglycerides as well as in the myelin and microsomal fractions. In addition, the levels of 20:4(n - 6) and 22:4(n - 6) were decreased. The levels of 20:4(n - 6), 22:4(n - 6), and 22:5(n - 6) were higher in the brain phosphoglycerides of rats maintained on the corn oil-supplemented diet than on the lab chow control diet, and the elevation in these acyl groups was more evident in the microsomal fraction than in the myelin fraction.