Glucocorticoid deprivation alters in vivo glucose uptake by muscle and adipose tissues of GTG-obese mice

Abstract

The effect of 1 wk of glucocorticoid deprivation by surgical adrenalectomy (ADX) on tissue 2-deoxy(-)[U-14C]glucose (2-DG) uptake and hepatic glucose production (HGP) was assessed in conscious, catheterized mice 5 wk after the induction of obesity with gold thioglucose (GTG). Despite the prevailing hyperglycemia and hyperinsulinemia, glucose uptake by heart, quadriceps muscle, and interscapular brown adipose tissue (BAT) of GTG-obese mice was unchanged compared with controls, suggesting that the hyperglycemia of GTG-obese mice is able to compensate for the insulin resistance of these tissues. In contrast, epididymal white adipose tissue (WAT) of GTG-obese mice showed increased glucose uptake with hyperglycemia and hyperinsulinemia. ADX decreased the hyperglycemia and lowered the elevated glycogen content of the liver of GTG-obese mice. ADX reduced glucose uptake by heart and WAT of control and GTG-obese mice, consistent with the concomitant decrease in insulinemia. Glucose uptake by muscle of control and GTG-obese mice was not significantly decreased after ADX despite the decrease in insulin, and ADX increased glucose uptake by BAT of GTG-obese mice, suggesting increased sympathetically mediated thermogenesis in this tissue. HGP was increased in GTG-obese mice compared with controls, and ADX significantly reduced HGP in both GTG-obese and control mice. These results suggest that the improved glucose tolerance of ADX GTG-obese mice and ADX control mice is due to a decrease in HGP rather than an increase in peripheral glucose uptake.