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 corn pounds on the activity of 92-amino-1,3,4-thiadiazole against transplanted mouse leu kemia B892 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 “niacinantagonist― represents several different meta bolic activities, all reversible by niacin.