Glucose production rates in type 1 glycogen storage disease

Glucose production rates were measured in six patients with glycogen storage disease type 1 (five type 1A, one type 1B) using a primed continuous infusion of either [3-3H]glucose or [6,6-2H2]glucose. In four patients exogenous glucose was needed to maintain normoglycaemia. At blood glucose concentrations of 2.3-4.7 mmol/L, the endogenous glucose production rates were between 34 and 100% of that predicted for healthy subjects. No relationship was found between the blood glucose concentration and glucose production rates but there was a positive correlation between that of blood lactate and glucose production rate. The initial steady state was perturbed either by reducing the exogenous glucose infusion rate or by giving intravenous glucagon (20 micrograms/kg) or alanine (0.1-0.2 g/kg). Reducing the exogenous glucose infusion rate had little short term effect on glucose production rate. Intravenous glucagon increased the glucose production rate as well as blood glucose and lactate concentrations. A bolus of alanine (0.2 g/kg) given intravenously increased the glucose production rate and blood glucose concentrations but blood lactate concentrations fell. In four of the patients the studies were repeated under similar conditions and the glucose production rate was higher in all patients. We conclude that the glucose production rate is not fixed but varies with the prevailing metabolic status, a finding that has implications for the treatment of type 1 glycogen storage disease.