Fig. 4. -Adrenergic induction of the hsp70 gene involves a PTX-sensitive G-protein, PLC and a Ca²⁺-dependent PKC. Pretreatment of transfected oyster hemocytes with (A) PTX, (B) the PLC inhibitor U73122, (C) the PKC inhibitor calphostin C (CalC) and (D) the Ca²⁺-dependent PKC isoform inhibitor Gö 6976 blocked the PE-induced increase in luciferase activity. Pretreatment with the PKA inhibitor H-89 (C) had no significant effect. Data are means and standard errors of three replicate experiments. Asterisks denote significant (P<0.01) differences from samples incubated in the presence of 1 µM PE alone. Bas indicates luciferase activity in samples incubated in the absence of drugs.