[Effects of different types of nutritional imbalance on lipid peroxidation and viscosity of membrane lipids].

For 90 days male August rats were kept on 5 diets: (I) balanced semisynthetic, (II) with amino acid unbalance, (III) with excess polyunsaturated fatty acids (PUFA), (IV) with vitamin E deficiency, and (V) polyunbalanced (amino acid unbalance, excess PUFA, vitamin E deficiency). In liver microsomes, the authors studied the kinetics of malonic dialdehyde accumulation in the course of NADPH-dependent lipid peroxidation (LP) and microviscosity of the lipid phase of microsomal membranes according to eximerization of the pyrene fluorescent hydrophobic probe. The microsomes of the animals fed diets I, III and IV showed on the average a 50 to 55% increase in the rate of MDA formation, whereas those of rats on diet V a 78% increase as compared with appropriate characteristics in the animals fed diet I. A good correlation was established between the decrease in the pyrene eximerization rate and accumulation of lipid peroxides: r = 0.09 (P less than 0.05). The possibility of affecting LP in the membranes by the goal oriented modification of the diet is discussed. The participation of proteins, lipids and tocopherol in the maintenance of the membrane structure is described.