Metabolism of labeled nicotinamide coenzyme in different organs of mice and rats.

Abstract

SummaryReplacement of radioactive NAD in different organs of rats and mice was found to be most rapid in kidney, liver, and intestine and slowest in brain, muscle, and testis. Experiments with nicotinamide as precursor indicate that nicotinamide derived from NAD degradation is extensively reutilized in the latter organs. Injection of labeled nicotinamide together with a large amount of cold nicotinic acid suggests that this reutilization in brain and muscle probably does not involve deamidation of nicotinamide to nicotinic acid.