Effects of dexamethasone on glucose transport by skeletal muscles of obese (ob/ob) mice.

Adrenalectomy normalized basal and insulin-stimulated glucose transport in the perfused hindquarter of the obese (ob/ob) mouse. Dexamethasone treatment of adrenalectomized obese mice for 9 days significantly reduced both the basal and insulin-stimulated uptake of (3H)-2-deoxy-D-glucose in hindlimbs of adrenalectomized mice to levels similar to those of intact ob/ob mice. Five hours after injection of dexamethasone in vivo and following 5 hours of perfusion in vitro there was a 10 percent reduction in basal 2-deoxy-D-glucose uptake in both groups. In muscles perfused with dexamethasone in vitro, the stimulation of 2-deoxy-D-glucose uptake by insulin was greater than in those muscles perfused with vehicle alone. Five hours of treatment in vivo also resulted in a significant increase in liver tyrosine aminotransferase activity, and a decrease in muscle glycogen synthetase activity ratio. These data suggest that the effect of glucocorticoids on lowering glucose transport in the skeletal muscle of obese ob/ob mice is a direct one.