Release of intestinal diamine oxidase by histamine in rats

• Published in: Canadian journal of physiology and pharmacology Vol. 61; no. 4; p. 349
• Main Authors: Wollin, A, Navert, H
• Format: Journal Article
• Language: English
• Published: Canada 01.04.1983
• Subjects: Amine Oxidase (Copper-Containing) - metabolism; Animals; Dose-Response Relationship, Drug; Female; Heparin - pharmacology; Histamine - pharmacology; Intestines - enzymology; Lymph - enzymology; Proteins - analysis; Rats; Rats, Inbred Strains
• ISSN: 0008-4212; 1205-7541
• DOI: 10.1139/y83-053

Diamine oxidase activity was measured in the intestinal mucosa, lymph, and in the serum of rats, to determine whether histamine, a substrate of diamine oxidase, liberates this enzyme from its mucosal storage site(s). Histamine induced a sharp rise in intestinal lymph flow, lymph protein, and lymph diamine oxidase, lasting less than 1 h after the histamine injection. The rise in lymph diamine oxidase activity was dose dependent over a narrow concentration range (0.05-0.2 mmol/kg, i.v. and 0.15-0.6 mmol/kg i.d.). It did not correlate with the dose dependent increase in lymph flow or lymph protein. A single maximal intraduodenal dose of histamine caused a 41.6-fold increase in the lymph diamine oxidase activity and a 2.4-fold increase in the serum enzyme level temporarily. A second injection of histamine, 2 h after the first, resulted in a comparatively smaller increase in the lymph enzyme. The extent of the reduction was dependent on the magnitude of the first injection. The results suggest that histamine causes a limited liberation of diamine oxidase from the intestinal mucosa. The function of this enzyme release may be a protective response by the mucosa to reduce toxic levels of free histamine, either liberated by the mucosal tissue or absorbed from the intestinal lumen.