[Electrical stability of mitochondrial membranes: the role of thyroid hormones and the fat component of the diet].

Electric stability of the membranes of the mitochondria and liposomes formed from mitochondrial lipids was studied. The mitochondria were isolated from the liver of euthyroid or hyperthyroid rats kept on the diets with varying degree of food fat unsaturation. In the first group animals, butter was used as a fatty component of the diet whereas the second group animals received sunflower oil. The electric stability of the membranes of the mitochondria and respective liposomes appeared lower in the first group animals as compared with those in the second group animals. Hyperthyrosis was accompanied by the increased electrical stability of mitochondrial lipids in both the groups. At the same time the liposomal membranes were similar as regards the electric stability, whereas the electric stability of the mitochondrial membranes in the first group hyperthyroid and euthyroid rats was lower than in the organelles of the second group animals. It is thus assumed that the electric stability of the mitochondria is determined not only by the chemical composition of lipids but also by other factors.