Lipid metabolism in brain tissue explants.

Abstract

Abstract— Tissue explants from frontal lobes of rat brain were used for the study of cerebral fatty acid metabolism. After tissues had been maintained in serum‐supplemented medium, a lipid‐free medium was substituted and metabolic studies were carried out. Under these conditions explants continued to take up lipid precursors for at least 48 h, as judged by incorporation of dl‐[2‐14C]mevalonic acid into cellular lipids. [l‐14C]Stearic acid and [l‐14C]palmitic acid were bound to cells as the free fatty acids, or incorporated into neutral lipids (particularly triglycerides), glycolipids and phospholipids. In the galactolipid fraction, cerebrosides were the principal radioactive lipids. Choline phosphoglycerides, ethanolamine phosphoglycerides, inositol phosphoglycerides and serine phosphoglycerides were the principal radioactive phospholipids. Fatty acids were incorporated into cellular lipids either unchanged or after desaturation, chain elongation, or both. Maximum incorporation of stearate occurred in tissues derived from 3‐day‐old animals. With increasing age the uptake of fatty acid dropped sharply.When the labelling of lipids as a function of time was followed in 3‐day‐old animals, triglycerides and choline phosphoglycerides were the first fractions to take up labelled stearate. Labelling of cerebrosides occurred slowly, only becoming evident after 24 h. These studies exemplify the usefulness of tissue explants for prolonged metabolic studies in normal and pathological specimens of brain.