N-Methyl-4-pyridone-5-carboxamide as a metabolite of nicotinic acid in man and monkey.

In previous experiments reported from this laboratory (1) N-methyl-4-pyridone-5-carboxamide was isolated from rat urine and identified as the major urinary metabolite of the pyridine nucleotides. Recently Wieland et al. (2) synthesized this 4-pyridone and have found their synthetic product to be identical with the compound isolated from rat urine. Experiments have now been carried out to determine whether the pyridine nucleotides are similarly metabolized by the monkey and the human. In the case of the monkey, C14-nicotinic acid was injected into the animal, whereas the isotope dilution method was used to study the excretion of N-methyl-4-pyridone-5-carboxamide and N-methyl-2-pyridone-5-carboxamide by the human.