Changes in the intracellular activity of caspase-3, -8 and -9. Changes in the intracellular activity of caspase-3, -8 and -9 in the cells treated with NOC-18, under low-glucose condition, were expressed as their fold increments in the cells treated with NOC-18 to the untreated cells. Both the activity of caspase-3 and -9 significantly increased in the cells treated with NOC-18 (caspase-3, P < 0.0001; caspase-9, P < 0.005); however, there was no difference in the activity of caspase-8 between the treated cells and the untreated cells.