Effect of food intake on urinary excretions of histamine, N tau-methylhistamine, imidazole acetic acid and its conjugate(s) in humans and mice.

The urinary excretions by young healthy men of histamine and its metabolites, N tau-methylhistamine, imidazole acetic acid, and imidazole acetic acid conjugate(s), increased 1-3 h after food intake. The increase was seen even after the intake of konnyaku (mannan) as a protein-deficient food, suggesting that physical stimulation of the gastric mucosa by food is the main cause of histamine release. This suggestion was confirmed by the following findings in patients and mice. In patients with stomach diseases, gastrectomy resulted in decreases in the excretion of histamine and its metabolites in the urine, and patients subjected to intravenous hyperalimentation excreted less histamine and its metabolites in the urine than normal subjects. In mice, a correlation of histamine excretion with food intake was demonstrated experimentally. Namely, mice fed only during the night (21:00-0:00) showed increased excretions of histamine and its metabolites at 23:00-3:00, whereas those fed in the morning (9:00-12:00) showed increased excretions of those compounds at 11:00-15:00. All these results are consistent with the idea that urinary histamine and its metabolites mainly originate from the stomach.