ROLE OF ARACHIDONIC-ACID METABOLISM IN THYMOCYTE APOPTOSIS AFTER IRRADIATION

The present study demonstrates that DNA fragmentation, nuclear pycnosi s and trypan blue staining of irradiated thymocytes is prevented by in hibition of the lipoxygenase pathway of arachidonic acid metabolism an d is not affected by cyclooxygenase inhibition, Exposed to irradiation [H-3]arachidonic acid-labeled thymocytes release radioactive products to the external medium, The process is blocked by the lipoxygenase in hibitor, nordihydroguaiaretic acid. Thus, it can be concluded that irr adiation activates arachidonic acid metabolism and that lipoxygenase m etabolites play an important role in thymocyte apoptosis.