UP-REGULATION OF GLUCOSE-METABOLISM BY GRANULOCYTE-MONOCYTE COLONY-STIMULATING FACTOR

Alterations of glucose metabolism were investigated for 6 hours following an intraarterial injection of murine recombinant granulocyte-monocyte colony-stimulating factor (GM-CSF) (30-mu-g/kg body weight). GM-CSF resulted in a transient elevation of plasma glucose. The rate of whole body glucose appearance, as measured by infusion of [6-H-3]glucose, was increased by about 10 % between 0.5 and 3 hours following GM-CSF injection. In vivo glucose utilization of individual tissues was investigated by the tracer 2-deoxyglucose technique. At 30 min, GM-CSF increased glucose utilization by 80-90 % in liver and lung, and 50-60 % in skin and spleen. At 3 and 6 hours, glucose utilization by these tissues returned toward control levels except for lung. There was a 40-50 % increase in glucose utilization by skeletal muscle 30 min after GM-CSF which was sustained for 6 hours. Glucose utilization of testis, ileum and kidney did not change significantly. Plasma concentrations of insulin, glucagon and tumor necrosis factor were not altered in response to GM-CSF. These findings indicate that some of the acute metabolic effects of a short-term administration of GM-CSF are observed in macrophage-rich tissues, and suggest that GM-CSF may be involved in the metabolic upregulation of immunologically active tissues.