Essential fatty acid deficiency and mitochondrial function

Abstract

Some biochemical and ultrastructural properties of liver mitochondria from rats fed diets deficient in essential fatty acids (EFA) are described. Within 2 weeks, the proportions of arachidonic and linoleic acids showed marked decreases, and large changes in the fatty acid composition of cardiolipin and phosphatidylcholine, but not phosphatidylethanolamine, occurred. In general, the activites of inner membrane functions, such as respiration, oxidative phosphorylation, and the capacity for energized translocation of mono- and divalent cations, were largely unchanged by EFA deficiency. Ion transport-induced mitochondrial swelling was also unaltered, but mitochondria from EFA-deficient animals were more resistent to lipid peroxidation, and hence to peroxidative swelling. Oscillations of mitochondrial volume in response to ion transport in EFA-deficient preparations were slower, and the amplitude of the oscillatory response upon repeated O 2 pulses was diminished to a greater extent, in mitochondria from EFA-deficient animals. An electron microscope study of rat liver mitochondria revealed the following ultra-structural differences due to EFA deficiency: (1) inner membranes were more irregularly organized in vitro, and (2) the mitochondria were larger in situ, and enlarged more upon isolation than did mitochondria from rats on EFA-supplemented diets. These changes occurred within 4 weeks.