LEVELS OF METABOLITES AND PRODUCTION OF GLUCOSE IN LAMPREY BRAIN

—The levels of ATP, phosphocreatine, glucose, glucose‐6‐P., lactate, and glycogen have been measured in brains and spinal cords of lamprey larvae. Levels of glycogen in the brains were high, sometimes exceeding 100 m‐moles of glycosyl units/kg wet weight. Isolated brains incubated in oxygenated saline exhibited the same levels of ATP and phosphocreatine as brains of intact animals. The level of glucose in tissue water of isolated brains approximated that found in the medium, except at low concentrations where the brains maintained levels of glucose many times that of the medium. It is demonstrated that under metabolic stress lamprey brains produce glucose by the breakdown of glycogen and the probable action of a glucose‐6‐phosphatase. The hypothesis is proposed that cells of the brain exchange glucose by this mechanism. Copyright © 1969, Wiley Blackwell. All rights reserved