Gastrin levels after proximal gastric vagotomy.

Fasting gastrin levels were compared in patients before and after selective vagotomy and before and after proximal gastric vagotomy. In both groups there was a significant rise in fasting gastrin levels following the operative procedures, but no significant difference between gastrin levels after selective vagotomy and after proximal gastric vagotomy was found. The gastrin output in response to protein in six patients with proximal gastric vagotomy studied within two weeks of operation did not differ from their pre-operative response. Thus retention of an innervated antrum as in proximal gastric vagotomy neither results in fasting gastrin levels which are higher than when the antrum is denervated, nor in excessive gastrin levels after protein ingestion. In both post-operative groups insulin hypoglycaemia produced a similar rise in gastrin levels. Insulin hypoglycaemia is therefore not a specific test of vagal function and other mechanisms may be involved in the increase in acid secretion seen after insulin.