[2 possible mechanisms of action of thyroxine on mitochondrial swelling]

The effect of thyroxin on different types of mitochondrial swelling (induced by calcium, detergents, valinomycine, or lipid peroxidation) was investigated. Under conditions favourable for phospholipase-induced mitochondrial swelling on account of phospholipase activation (low Mg2+ concentration, and Ca2+ present in the incubation medium) the hormone proved to accelerate the swelling of the organellae. When phospholipase-induced mechanism of mitochondrial swelling was inhibited (high Mg2+ concentration) thyroxin depressed considerably the swelling of organellae induced by lipid peroxidation due to its antioxidant action.