Activation of lipid peroxidation in liver mitochondria of rabbits with hyperthyroidism

: Lipid peroxidation (LPO) in liver mitochondria of normal and hyperthyroid rabbits was studied by recording chemiluminescence of mitochondrial suspensions, induced by Fe2+. It was shown that in mitochondria of the hyperthyroid animals, there takes place an increase in the "slow flash" amplitude of chemiluminescence and reduction in the latent period of the luminescence development, as compared to the similar phenomena in normal animals. Characteristic changes were also seen upon recording chemiluminescence of suspensions of the lipids isolated from mitochondria of normal and hyperthyroid animals. These data attest to LPO activation in liver mitochondria during hyperthyrosis. LPO activation is not the result of a direct action of thyroxine on the mitochondria, since the addition of the hormones to organelles in different concentrations (3.25 x 10(-8)- 1.6 x 10(-7) mol/mg protein) did not alter the chemiluminescence parameters. It is suggested that LPO activation seen in liver mitochondria during hyperthyrosis is determined by an increase in the unsaturated index of fatty acids of mitochondrial lipids.