Zinc and 17β-estradiol induce modifications in Na+/H+ exchanger and pyruvate kinase activity through protein kinase C in isolated mantle/gonad cells of Mytilus galloprovincialis

We investigated the transduction pathway mediated by Zn and 17β-estradiol in isolated mantle/gonad cells of the mussel Mytilus galloprovincialis. Both the essential metal Zn, and the estrogen 17β-estradiol, caused an increase in intracellular pH (pHi) of isolated mantle/gonad cells of the mussel M. galloprovincialis, thus indicating the activation of the Na+/H+ exchanger (NHE). The observed effect was inhibited by EIPA (20 nM), a specific NHE inhibitor, thus verifying NHE activation. Protein kinase C (PKC) also seemed to play an activating role in zinc and 17β-estradiol effects on NHE and PK activity. In addition, the glycolytic enzyme pyruvate kinase (PK) was increased after zinc, while it was decreased after 17β-estradiol treatment. It is noteworthy that, both the latter effects were reversed in the presence of EIPA, indicating the involvement of NHE in the signaling mechanism. cAMP seems to participate in the signaling mechanism induced by Zn but not to that induced by 17β-estradiol. The potential implication of the heavy metal and 17β-estradiol on the reproductive activity of the marine animals is discussed.