Enhanced adrenergic mechanisms in glucose output from the kidney of diabetic rats

To elucidate the possible role of the kidney in glucose regulation in diabetes, the renal effect of glycerol plus glutamine, hydrocortisone, glucagon, or epinephrine was investigated in streptozotocin-induced diabetic rats. This in vivo study bolus infused glutamine (100 microg/kg) plus glycerol (100 microg/kg), hydrocortisone (100 microg/kg), glucagon (250 microg/kg), or epinephrine (40 microg/kg) into nephrectomized rats, and measured plasma glucose level. In perfused rat kidney, the effect of glutamine (2 mmol) plus glycerol (2 mmol), hydrocortisone (1 mmol), glucagon (215 pmol), or epinephrine (2 nmol) infusion on glucose output was evaluated. The increase in blood glucose after infusion of glutamine plus glycerol, hydrocortisone, or glucagon was not altered by nephrectomy. However, the increase in blood glucose after epinephrine infusion was significantly blunted in nephrectomized rats. In perfused kidney, although the increase in glucose output after addition of glutamine plus glycerol, hydrocortisone, or glucagon was similar in control and diabetic rats, glucose output after epinephrine infusion was significantly higher in diabetic rats than in control rats. These results suggest that the adrenergic stimulation on renal glucose output may be enhanced in diabetes.