CHANGES IN PLASMA GLUCOSE EFFECT PER SE ON HEPATIC GLUCOSE METABOLISM

Activation of endogenous glucose production (EGP) was examined in non-diabetic (N=12) and type 1 diabetic (DM1, N=8) subjects while lowering plasma glucose (PG) from clamped euglycemia (~100 mg/dl; 5.6 mmol/L) to values just above the threshold for epinephrine (EPI) and glucagon secretion (~70 mg/dl; 3.9 mmol/L). To induce physiologic hyperinsulinemia (HIns), insulin infusions were fixed at 20% above the rate previously established that maintained euglycemia during somatostatin (250 5g/hr), glucagon (1.0 ng.kg-1.min-1), and GH (3.0 ng.kg-1.min-1) infusions without need for glucose infusion. In nondiabetic subjects, PG was reduced from 5.410.1 mmol/L to 3.910.1 mmol/L in the Experimental protocol, and held constant (5.310.2 mmol/L and 5.5mmol/L) in Control protocol. In the latter, with constant Hins (plasma insulin=12616 pmol/L) and euglycemia, EGP (estimated by [3H-3]-glucose) fell to values 40% of basal (p