Streptozotocin-Induced Diabetes Increases Fructose 2,6-Bisphosphate Levels and Glucose Metabolism in Rat Macrophages

The acute effects of streptozotocin-induced diabetes on several parameters of glucose metabolism were investigated in rat peritoneal macrophages. These cells accumulated in vitro about twofold more fructose 2,6-bisphosphate in the presence of increasing glucose concentration than cells from normal rats, and an increased production of lactate was observed. Phosphofructokinase-1, phosphofructokinase-2, hexokinase, and pyruvate kinase activities were increased in cells from diabetic rats compared with those from normal rats. Transport of 2-deoxy-D-glucose was increased in cells from diabetic rats. [U-¹⁴C]Glucose incorporation into glycogen was also increased in cells from diabetics and the ¹⁴CO₂ liberation was less than in cells from normal animals. Moreover, macrophages from diabetics did not possess a more active pentose phosphate pathway (measure with [1-¹⁴C]glucose oxidation) nor a greater production of superoxide anion (index of activation of macrophages) than in cells from normal animals.