[Decrease of lipid peroxidation in liver mitochondria isolated from rabbits with hypothyroidism].

A study was made of chemiluminescence of mitochondria and liposomes formed of mitochondrial phospholipids obtained from the liver of normal and thyroidectomized rabbits. The Fe2+-induced chemiluminescence of mitochondria was characterized by a decrease in the amplitude of "slow flash" and by an increase in the latent period of this parameter occurrence under hypothyrosis. This is accounted for by the decreased rate of lipid peroxidation (LPO) in mitochondria, caused by the deficiency of thyroid hormones in the body. Forty-one hours after a single administration of L-thyroxine (300 micrograms/kgbw) to the rabbits the intensity of chemiluminescense of mitochondria and liposomes not only returned to that of the preparations obtained from the normal animals but even exceeded it approximately 1.5-fold. Apparently, such an abrupt intensification in LPO reactions is consequent on the increased rate of unsaturation of fatty acids in mitochondrial lipids, caused by the hormone administered.