DECREASED MYOCARDIAL GLUCOSE-UPTAKE DURING ISCHEMIA IN DIABETIC SWINE

The purpose of the study was to assess myocardial glucose uptake in no ndiabetic (n = 5) and streptozotocin-diabetic (n = 6) Yucatan miniatur e swine under matched hyperglycemic and hypoinsulinemic conditions. Fa sting conscious diabetic swine had significantly higher plasma glucose levels (20.9 +/- 2.6 v 5.2 +/- 0.3 mmol/L) and lower insulin levels ( 6 +/- 1 v 14 +/- 4 mu U/mL) than nondiabetic animals. Myocardial gluco se uptake was measured in open-chest anesthetized animals under aerobi c and ischemic conditions 12 weeks after streptozotocin treatment. Cor onary blood flow was controlled by an extracorporeal perfusion circuit . Ischemia was induced by reducing left anterior descending (LAD) coro nary artery blood flow by 60% for 40 minutes. Animals were treated wit h somatostatin to suppress insulin secretion, and nondiabetic swine re ceived intravenous (IV) glucose to match the hyperglycemia in the diab etic animals. The rate of glucose uptake by the myocardium was not sta tistically different under aerobic conditions, but was significantly l ower in diabetic swine during ischemia (0.20 +/- 0.08 v 0.63 +/- 0.14 mu mol . g(-1). min(-1), P < .01). Myocardial glucose transporter (GLU T4) protein concentration was decreased by 31% in diabetic swine. In c onclusion, 12 weeks of streptozotocin diabetes in swine caused a signi ficant decrease in myocardial GLUT4 protein and a decrease in myocardi al glucose uptake during ischemia. Copyright (C) 1997 by W.B. Saunders Company.