Lipoxygenase-mediated secretory effect of canatoxin the toxic protein from Canavalia ensiformis seeds.

Canatoxin was shown to induce serotonin release from rabbit platelets and rat brain synaptosomes, as well as to release insulin from isolated pancreatic islets. All these effects were dose-dependent and were inhibited by lipoxygenase inhibitors, such as nordihydroguaiaretic acid and esculetin, but not by indomethacin, a cyclooxygenase inhibitor. The data suggest that canatoxin-induced secretory effect results from the activation of the lipoxygenase pathway which would elicit exocytosis. Thus, canatoxin might be a useful tool for the study of biological events that involve lipoxygenase mediation.