Excretion of tryptamine and indole-3-acetic acid in urine of rats with intestinal diverticula

¹ Department of Medicine, Boston University School of Medicine, and Boston Veterans Administration Hospital, Boston, Massachusetts

The urinary excretion of indoleacetic acid, but not of tryptamine, is increased in rats with localized intestinal stasis resulting from the surgical formation of midintestinal diverticula. Significant quantities of tryptamine, however, are produced within the intestinal pouches of these animals. When the conversion of tryptamine to indoleacetic acid is maximally inhibited with iproniazid, tryptamine accumulates in the urine of the rats with diverticula to the same extent as it does in control animals. The monoamine oxidase activity of tissues from rats with diverticula is neither increased nor resistant to iproniazid inhibition. Injection of large quantities of tryptamine directly into the intestinal pouches produced no significant increase in urinary tryptamine or indoleacetic acid. It therefore appears that tryptamine produced within the diverticula does not significantly contribute to the indoleacetic acid appearing in the urine of these rats.