Acetyl-L-carnitine modulates glucose metabolism and stimulates glycogen synthesis in rat brain

The effects of acetyl-L-carnitine on cerebral glucose metabolism were investigated in rats injected with differently C-14- and C-13-labelled glucose and sacrificed after 15, 30, 45, and 60 min. Acetyl-L-carnitine was found to reduce total (CO2)-C-14 release from [U-C-14]glucose along with the decrease in [1-C-13]glucose incorporation into cerebral amino acids and tricarboxylic acid cycle intermediates. However the C-13 labelling pattern within different carbon positions of glutamate, glutamine, GABA, and aspartate was unaffected by acetyl-L-carnitine administration. Furthermore, the cerebral levels of newly-synthesized proglycogen were higher in rats treated with acetyl-L-carnitine than in untreated ones. These results suggest that acetyl-L-carnitine was able to modulate cerebral glucose utilization and provide new insights on the mechanisms of action of this molecule in the central nervous system. (C) 1998 Elsevier Science B.V. All rights reserved.