Nicotinic acid and nicotinamide metabolism in ascites cells in vitro.

The studies reported here are primarily concerned with the metabolism of vitamin-containing nucleotides in intact cells. Holzer, Friedrich, and Grisebach (I) have reported that the Ehrlich ascites cells incorporated nicotinic acid-C4 slowly into nicotinamide adenine dinucleotide. Since, under the same conditions, nicotinamide-Cl4 was rapidly incorporated into nicotinamide adenine dinucleotide, they concluded that the nicotinamide is the form of the vitamin most readily utilized by these cells. The present study, which was in part stimulated by these observations, indicates that nicotinic acid-C4 is readily incorporated into nicotinamide adenine dinucleotide provided L-glutamine is made available to the cells.