Gastric secretory response to graded insulin hypoglycemia

Abstract

Variable dosages of intravenous insulin, <0.075 U/kg (range, 0.01– 0.06 U/kg), 0.075 U/kg, 0.1 U/kg, and 1.5 U/kg were used in 10 dogs fitted with a Thomas fistula. The course of insulin hypoglycemia was monitored continuously by the AutoAnalyzer and plasma steroid (hydrocortisone) levels were determined hourly after insulin. Total acid output during the 2nd and 3rd hr after 1.5 U/kg insulin was greater ( P < 0.01) than after 0.1 U/kg, but not during the initial hour. Minimal or no gastric secretion occurred with 0.075 U/kg insulin or less. Increase in flow of gastric contents occurred if blood sugar concentration was 40 mg/100 ml or less (potassium ferricyanide method). Rate of blood sugar and concentrations of less than 40 mg/100 ml were not correlated statistically with total acid output 30–60 min after insulin. In most experiments, increase in flow of gastric contents occurred simultaneously to or followed the lowest point reached by the blood sugar. Plasma hydrocortisone levels were highest with 1.5 U/kg insulin, and remained elevated up to 5 hr.