Effect of Enterectomy on Synthesis of Niacin in the Rat.

Abstract
Summary 1. The effect of removal of the intestinal tract below the pancreas on the ability of the rat to form niacin derivatives in response to tryptophan administered subcutaneously has been determined. 2. The response in urinary N'methyl nicotinamide was not affected. by enterectomy. 3. “Free” and “total” urinary niacin as measured by microbiological assay before and after acid hydrolysis respectively were increased in enterectomized animals although the increase was not as great as in intact animals. 4. The results suggest that the tissues are the primary site of the formation of niacin derivatives in the rat in response to large doses of tryptophan.