Male C57BL/6 mice were induced to diabetes by giving one of three doses of streptozotocin (STZ; 65, 75, 100 mg/kg BW) alone or in combination with subsequent high-fat diet. Mice were treated with a daily intraperitoneal dose of 250 mg/kg BW isoncotinamide. Isonicotinamide effectively prevented hyperglycemia induced by high doses of STZ (75 and 100 mg/kg BW) alone, and also low-dose (65 mg/kg BW) in combination with a high-fat diet. The protective effects were associated with decreased apoptosis of beta-cells.

Human myeloid leukemia (HL-60) cells were cultured in RPMI 1640 medium with 100 U/mL penicillin, 100 microgram/mL streptomycin, 2 mM L-glutamine, and 10% heat-inactivated fetal bovine serum at 37 deg-C in a 5% CO2 atmosphere. Cells were treated with 1 - 10 mM isonicotinamide. Apoptosis was monitored by flow cytometry. Isonicotinamide had a strong effect of inducing DNA fragmentation leading to apoptosis.