Abstract
The secretion of gastrin in response to insulin has been assumed to be due to a vagal release of gastrin. In order to confirm this, gastrin concentrations in serum were determined by radioimmunoassay in unoperated and vagotomized ulcer patients. A moderate and sustained increase in serum gastrin concentrations was demonstrated in 23 unoperated patients (from a mean of 104 to a mean of 148 pg per ml serum), in 19 patients with a complete vagotomy (from a mean of 103 to a mean of 140 pg per ml serum), and in 25 patients with an incomplete vagotomy (from a mean of 127 to a mean of 178 pg per ml serum). The increase began 30 minutes after insulin injection and lasted for more than 1 1/2 hours. The fact that a definite increase could be demonstrated in all groups of patients shows that vagotomy does not abolish the gastrin response to insulin hypoglycaemia.