Fig. 6. -Adrenergic induction of the hsp70 gene does not involve the MAP kinase cascade. Pretreatment of transfected oyster hemocytes with the MAP kinase inhibitor PD098059 (PD) did not block the PE-induced increase in luciferase activity. Exposure of cells to 100 µM PD098059 resulted in increased luciferase activity in both PE-treated and -untreated samples, suggesting that MAP kinases repress the induction of the hsp70 gene promoter in oyster immune cells. Data are means and standard errors of three replicate experiments. Asterisks denote significant (* for P<0.05, ** for P<0.01) differences from samples incubated in the absence of drugs (white bars) or in the presence 1 µM PE alone (hatched bars). Bas indicates luciferase activity in samples incubated in the absence of drugs.