The effect of methylnitrosourea intoxication on the fatty acid pattern of myelin lipids

The effect of intravenous administration of methylnitrosourea (MNU), 60 mg/kg body weight to adult BD IX rats for 6 consecutive days, on the fatty acid composition of myelin lipids has been examined. The results of our investigations show that the fatty acid spectrum of all myelin lipid components was significantly altered after MNU treatment. The comparison of the fatty acid composition of the myelin phospholipids and the cholesterol esters formed MNU intoxication did not speak in favour of the hypothesis that enhanced lipolysis and thus the fatty acids liberated mainly from phospholipids are responsible for the increased esterification of cholesterol observed in toxic myelinopathies. It rather confirms the thesis that enhanced esterification of cholesterol is one of the early, independent events occurring in the lipid layer of the myelin sheath in the course of demyelination. The observed changes in the fatty acyl spectrum of various myelin lipids may weaken the stability of the myelin lipid layer, and thus constitute another factor in the pathomechanism of toxic myelinopathies.