Oligodendrocytes use lactate as a source of energy and as a precursor of lipids

Lactate is an important metabolic substrate for the brain during the postna tal period and also plays a crucial role in the traffic of metabolites betw een astrocytes and neurons. However, to date there are no clues with regard to lactate utilization by oligodendrocytes, the myelin-forming cells in th e brain. In the present work, lactate utilization by oligodendrocytes in cu lture was investigated and compared with its utilization by cultured neuron s, type 1 and type 2 astrocytes. Our results clearly indicate that oligoden drocytes readily use lactate both as a metabolic fuel and as a precursor to build carbon skeletons. Oligodendrocytes oxidize lactate at a higher rate than that observed for neurons and astrocytes, and their rate of lipid synt hesis from lactate was at least 6-fold higher than that found in astrocytes or neurons. The rate of glucose utilization through different pathways was also investigated. The flux of glucose through the pentose phosphate pathw ay and the rate of lipid synthesis were at least 2-fold higher in oligodend rocytes than in astrocytes or neurons. These findings indicate that oligode ndrocyte metabolism is designed specifically for the synthesis of lipids, p resumably those of myelin. (C) 2001 Wiley-Liss, Inc.