Hans Mohrhauer

Effect of Linolenic Acid Upon the Metabolism of Linoleic Acid

Weanling rats were fed a fat-free diet supplemented with various ratios of corn and linseed oils to furnish a constant dietary level of linolenate at 1% of calories and levels of linoleate from 0.3 to 17.3% of calories. The fatty acid composition of the total liver lipids was analyzed by gas chromatography. Increasing amounts of dietary linoleate suppressed the levels of the 20:5, 22:5 and 22:6 metabo lites of linolenic acid in the liver lipids. The level of dietary vitamin E had no effect upon this phenomenon. When the level of dietary linoleate was increased, the level of 22:4 in the liver lipids, as well as the other metabolites of linoleate, was shown to increase.

TRACER EXPERIMENTS TO ASSESS METABOLIC CONVERSIONS OF POLYUNSATURATED FATTY ACIDS.

Fifteen groups of rats were maintained on diets free of fat or supplemented with different levels of linoleate, arachidonate or linolenate. After 100 days on the diets the rats were sacrificed and liver slices were incubated with acetate-1-14C. The individual fatty acids were separated by gas chromatography and their radioactivity was determined by liquid scintillation counting. The C20 esters were separated by GLC, collected, and the structures of the components were determined by ozonolysis. The acetate incorporation into the various polyunsaturated fatty acids was influenced by the previous dietary conditioning. The distributions of radioactivity indicated that metabolic reactions taking place in the rat liver are modified by dietary supply of essential fatty acids.