[Effect of thyroid state on the phospholipid regeneration rate of rat liver mitochondria]

The rate of phospholipid renewal in mitochondria of normal, hypothyroid, hyperthyroid and thyrotoxic rats was studied. Mitochondria were isolated from rat livers 24 and 48 hrs after administration of 3H-glycerol and 14C-palmitic acid. In mitochondria of hypothyroid animals, practically no phospholipid renewal is observed. In mitochondria of hyperthyroid and thyrotoxic rats, the rate of degradation of phospholipids labelled with glycerol, was approximately 1.5 times as low as that in controls. The decrease in the rate of renewal of the fatty acid residues in mitochondrial phospholipids was still more pronounced in hyperthyroid and thyrotoxic animals. Possible reasons for these changes connected with the thyroid state are discussed.