In vivo catabolism of histamine in the human stomach.

The importance of the stomach in the magnitude of excreted amounts of the major histamine metabolite in the urine was studied during total parenteral nutrition in five patients before and after total gastrectomy. In all subjects, a reduction in the 24-h urinary excretion of methylimidazoleacetic acid was observed. No corresponding effect was seen after an operation because of abdominal aortic aneurysm. In patients with duodenal ulcer disease and those submitted to a cholecystectomy because of cholecystolithiasis, we studied the catabolism of histamine in the stomach by injecting 14C-histamine directly into the portal vein and, simultaneously, 3H-histamine intra-arterially to the corpus fundus region of the stomach and subsequently determining the urinary excretion of 14C. 3H-histamine and their basic and acid metabolites, respectively. We found no apparent difference in the pattern of excreted 14C and 3H metabolites between the two patients groups, indicating that the catabolism of histamine in the stomach of patients with duodenal ulcer disease is similar to that in 'healthy' controls.