LIPID-COMPOSITION OF LIVER-MICROSOMES AND MITOCHONDRIA AFTER ACUTE AND CHRONIC GAMMA-IRRADIATION OF RATS

Acute gamma-irradiation of rats at doses of 100 and 270 Gy stimulates lipid synthesis and changes the lipid composition of liver cell organe lles. The content of cholesterol and cholesterol esters in microsomes increased at 100 Gy and decreased at 270 Gy, total phospholipid conten t remaining unchanged. The lipid content in mitochondria decreased con siderably 1 h after irradiation at 270 Gy. This change was significant ly less pronounced 47 h later. Under chronic gamma-irradiation (0.129 Gy/day), cholesterol and cardiolipin in mitochondria increased. The ch anges in lipid content caused by acute irradiation are presumed to be related to activated synthesis of lipids in the liver. The modificatio n of the lipid content of mitochondria observed in chronically irradia ted rats may indicate that energy-metabolizing liver cell systems are involved in the adaptation to irradiation.