Effects of nicotinamide and related compounds on the antileukemic activity of 2-amino-1,3,4-thiadiazole.

The effect of nicotinamide and a variety of nicotinamide analogs and related compounds on the activity of 2-amino-1,3,4-thiadiazole against transplanted mouse leukemia B82 has been tested. 5-Fluoronicotinamide, 6-aminonicotinamide, N-hydroxy-bis-methylnicotinamide, N-N′-methylene-bis-nicotinamide, DPN, and 3-acetylpyridine were as potent as nicotinamide and nicotinic acid in reversing the thiadiazole effect. Other nicotinamide analogs, the analogs of nicotinic acid, precursors and catabolic products of nicotinamide have not shown such activity. The results of this study have been compared with results obtained by another author in a different system. It has been concluded that the term “niacin antagonist” represents several different metabolic activities, all reversible by niacin.