Lipid composition and fluidity of liver mitochondria, microsomes and plasma membrane of rats with chronic dietary iron overload.

The effect of chronic dietary iron overload on the lipid composition and physical state of rat liver mitochondria, microsomes and plasma membranes was investigated. After 9 weeks of iron treatment, a significant decrease of polyunsaturated and a parallel increase of saturated fatty acids was observed in mitochondrial and plasma membrane phospholipids. By contrast, no appreciable modification of the fatty acid composition of microsomal membranes was detected. The cholesterol/phospholipid molar ratio as well as the lipid/protein ratio, did not reveal any significant difference in any of the fractions studies. Finally, no change in the molecular order of the various membranes, as assessed by electron spin resonance spectrometry, was observed following iron intoxication. These data indicate that, although in vivo chronic hepatic iron overload induces a modification of fatty acid profile in cellular structures consistent with the in vivo occurrence of lipid peroxidation, these changes do not bring about appreciable modifications of other physico-chemical parameters relevant to membrane integrity and cell viability.