Stimulative effect of epinephrine on glucose production and utilization rates in sheep using a stable isotope.

The rates of the production and utilization of blood glucose were measured during intravenous epinephrine infusion (2.0 nmol kg-1 min-1 for 1 hr) in sheep. An isotope dilution method with an infusion of [U-13C]glucose and nonsteady-state equations were used for the determination of blood glucose kinetics. Heart rate and concentrations of blood glucose, plasma free fatty acids, and lactate increased (P < 0.01), whereas plasma insulin concentrations tended to decrease (P < 0.06) during epinephrine infusion. The blood glucose turnover rate was 1.9 +/- 0.1 mg kg-1 min-1 before epinephrine infusion. The rate of blood glucose production increased (P < 0.01) to 6.4 +/- 0.5 mg kg-1 min-1 at 20 min after the initiation of epinephrine infusion. The blood glucose utilization rate increased (P < 0.05) gradually and reached 4.1 +/- 1.2 mg kg-1 min-1 at 60 min after the initiation of epinephrine infusion. These results suggest that in sheep, epinephrine stimulates the rates of both the production and the utilization of blood glucose and that hyperglycemia induced by epinephrine infusion is mainly due to a rapid enhancement in the rate of the production of blood glucose.