RELATIONSHIP BETWEEN FATTY-ACID ACCRETION, MEMBRANE-COMPOSITION, AND BIOLOGIC FUNCTIONS

Dietary fat affects metabolic pathways for phospholipid biosynthesis i n tissues in a coordinated fashion. This may be important to aspects o f development that concern phosphatidylcholine metabolism or regulator y processes that depend on signals from a changing milieu in the micro environment of the membrane. Dietary fat influences the phosphatidylet hanolamine (PE) composition in many membranes of the brain and retina and may be altered by small changes in the content of 20:4(6) and 22:6 (3). Membrane PE fatty acids that contain one, four, or six double bon ds and the ratio of 22:5(6) to 22:6(3) in PE that contains four to six double bonds are also affected. An increase in the omega 6 fatty acid content of membranes is associated with increased PE methyltransferas e activity and decreased phosphocholine transferase activity, thus ind icating a mechanism by which change in an exogenous factor (e.g., diet ary fat intake) may alter neural phospholipid biosynthesis. small chan ges in the composition of dietary fat intake change the composition of brain membranes during development. It is provocative to ponder wheth er diet could be used to induce formation of membrane structures that are more resistant to specific insults that cause degeneration of brai n structural material, to ensure optimal functional compositions, or t o reverse degenerative changes that occur in neural membrane structure and function.