Gastric acid secretion, serum-gastrin levels and psychomotor function under the influence of placebo, insulin-hypoglycemia, and/or bromazepam

Abstract

Gastric acid output, blood-glucose, serum-gastrin and psychomotor-performance were measured in four healthy subjects one hour before and two hours after the intravenous injection of (a) 2ml saline, (b) 0.2 U/kg b.w. insulin, (c) 0.1 mg/kg b.w. bromazepam. Each subject underwent one experiment of each type. The study was layed out as a Latin-square and analysed accordingly. Gastric acid secretion was measured by means of intragastric titration and a telemetering capsule; blood-glucose and serum-gastrin levels as well as psychomotor performance as a measure of vigilance were determined in 15-minute-intervals. In the saline series (a), none of the four parameters showed any systematic variation. In series (b), a bimodal response of acid output to insulin, initial inhibition and subsequent stimulation was observed in all subjects. Serum-gastrin levels showed only a slight and transient increase in the first thirty minutes. Psychomotor performance decreased markedly with progressing hypoglycemia, and increased when glucose levels rose again. In the bromazepan series (c), acid output and psychomotor performance decreased and, after the first hour, increased almost parallely, while glucose and gastrin levels remained unchanged. In series (d), an additive effect of insulin and bromazepam occurred: acid output and psychomotor performance were lower than after insulin alone; peak acid secretion, maximal hypoglycemia and peak of serum-gastrin were shifted to the right. It is concluded that the lowered basal as well as insulin-stimulated acid secretion after bromazepam is due to the central effect of the drug, and that this effect is mediated to the gastric glands directly via autonomic nervous pathways without involving a release of endogenous gastrin.