Histamine metabolizing activity of the stomach and intestine of the rat

¹ Worcester Foundation for Experimental Biology, Chicago Laboratory, and the Department of Clinical Science, University of Illinois College of Medicine, Chicago, Illinois

The squamous and glandular stomach and the small intestine of rats were studied for histamine-metabolizing activity, using 1 µg of C¹⁴-histamine as the substrate. The intestinal mucosa which contains much diamine oxidase (DO) (histaminase) was used as a control tissue. The squamous stomach metabolized approximately 70%; the glandular stomach, 40%; and the small intestine, 92% of the histamine. After adding the DO inhibitors, aminoguanidine and semicarbazide, to the minced tissue digest of all three tissues, approximately 12% of the histamine was still destroyed or unaccounted for.