Inhibitory effect of FO-1561 (S-adenosyl-L-methionine sulfate tosylate) on phospholipase A2.

The mechanism of the protective effect of FO-1561 (S-adenosyl-L-methionine sulfate tosylate) on mitochondria was investigated using rat heart muscle. FO-1561 stimulated CO2 production from palmitic acid in the mitochondria, indicating an increase in energy production. FO-1561 inhibited mitochondrial swelling induced by Ca2+ added exogenously or by addition of snake venom phospholipase A2. Moreover, FO-1561 inhibited phospholipase A2 activity directly. These results suggested that FO-1561 blocked mitochondrial swelling by inhibiting endogenous phospholipase A2 activity and so preventing decrease in palmitic acid oxidation.