Tumor promoter 12-O-tetradecanoylphorbol-13-acetate-induced insulin secretion: Inhibition by phospholipase A2- and lipoxygenase-inhibitors

Abstract In isolated pancreatic islets of rats, an insulin secretion was induced by a tumor promoter 12-o-tetradecanoylphorbol-13-acetate in a low glucose medium. The insulin secretion was inhibited by p-bromophenacyl bromide, mepacrine, nordihydroguaiaretic acid and 1-phenyl-3-pyrazolidinone but not by indomethacin. When the insulin secretion was suppressed by p-bromophenacyl bromide, the secretion was partially but not significantly restored by lysophosphatidyl choline and was fully restored by the simultaneous addition of arachidonic acid and lysophosphatidyl choline. These results suggest that activation of phospholipase A 2 and a lipoxygenase product(s) play important roles in the 12-o-tetradecanoylphorbol-13-acetate-induced insulin secretion.