Enhanced expression of group II phospholipase A2 gene in the tissues of endotoxin shock rats and its suppression by glucocorticoid.

We studied the regulation of group II phospholipase A2 (PLA2-II) gene in vivo, using endotoxin shock rat as a model for systemic inflammation. Administration of endotoxin into rats increased PLA2 activity in the plasma, as described by Vadas and Hay, using endotoxin-challenged rabbit. Specific absorption of this activity by anti-PLA2-II antibody indicated that the released PLA2 was PLA2-II. The levels of PLA2-II mRNA were elevated in the aorta, spleen, lung, and thymus but not in the liver and kidney. The tissues with high PLA2-II mRNA contents released a greater amount of PLA2-II than the tissues of control rats. These results suggest that in endotoxin shock rats, PLA2-II is synthesized de novo in the above tissues and released into circulation. Furthermore, our present study demonstrates that glucocorticoid suppresses the enhanced expression of the PLA2-II gene in the tissues of endotoxin shock rats.