INFLUENCE OF PROLONGED GLUCOSE INFUSIONS ON PLASMA INSULIN AND GROWTH HORMONE CONCENTRATIONS OF FOETAL LAMBS

Abstract

SUMMARY Chronically cannulated foetal lambs close to term were infused intravenously with glucose at rates of 40 or 70 mg/min for up to 5 days. Infusion at these rates increased the foetal plasma glucose concentration to values in the ranges 35–45 and 60–80 mg/100 ml respectively. There were related increases in plasma fructose and lactate concentrations. Foetal plasma insulin concentrations increased within the first hour and remained raised throughout infusion. Plasma insulin concentrations were significantly correlated with plasma glucose concentrations. The secretory response of insulin to subsequent glucose infusions at a rate of 140 mg/min was not increased by the previous prolonged glucose infusions. Glucose infusion resulted in decreased plasma growth hormone concentrations in three of the lambs infused, but over the total number of observations plasma glucose and growth hormone concentrations were not significantly correlated.