Stimulation of the secretion of plasminogen activator from activated murine macrophages by microtubule disrupting agents and deuterium oxide

Murine peritoneal macrophages activated in vivo with thioglycollate broth secrete plasminogen activator and other neutral proteinases. The secretion of plasminogen activator by these cells is potentiated by continuous culture with the microtubule destabilizing drugs colchicine, demecolchicine, vinblastine and nocodazole but not by the colchicine analogues trimethylcolchicinic acid and colchicoside which do not destabilize microtubules. Pulse treatment with colchicine for 2 hr or with nocodazole for 16 hr also stimulated plasminogen activator secretion. Deuterium oxide, which stabilizes microtubules, also stimulated secretion of plasminogen activator and failed to antagonize the effects of destabilizing agents on enzyme secretion. It is concluded that secretion of plasminogen activator is not dependent on an intact microtubular system.