Lihong Jiang1, Raimund I. Herzog2, Graeme F. Mason, Robin A. de Graaf, Douglas L. Rothman, Robert S. Sherwin2, Kevin L. Behar3
1Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA; 2Internal Medicine, Yale University School of Medicine; 3Psychiatry, Yale University School of Medicine
Hypoglycemia is a serious complication of type-1 diabetes in patients with tight glycemic control. Repeated exposure to hypoglycemia may lead to increased capacity of brain cells to utilize alternate fuels such as monocarboxylic acids. In this study rates of lactate utilization were determined in rats subjected to 3-days of antecedent recurrent hypoglycemia and in controls with 1H-[13C]MRS while receiving i.v. infusions of [3-13C]lactate. Metabolic rates were assessed under euglycemic and acute hypoglycemic conditions. Our results suggest that exposure to repeated hypoglycemia leads to increased capacity of neurons to oxidize lactate, providing a possible explaination for the phenomenon of hypoglycemia unawareness.