Protein Kinase C Potentiates Capacitative Ca²⁺ Entry That Links to Steroidogenesis in Bovine Adrenocortical Cells

抄録

I investigated the role of protein kinase C(PKC) in regulation of the capacitative Ca²⁺ entry and steroidogenesis in bovine adrenocortical(BA)cells.Thapsigargin(TG)-treatment depleted intracellular Ca²⁺ stores followed by induction of Ca²⁺ influx from the extracellular pool and also increasing of Mn²⁺ influx as an indicator of divalent cation influx in BA cells.Calphostin C, a PKC inhibitor, inhibited the TG-induced [Ca²⁺]_i elevation dose-dependently(0.1-1μM)and attenuated Mn²⁺ entry.Phorbol 12-myristate 13-acetate(PMA), an activator of PKC, potentiated the elevation of[Ca²⁺]_i and enhanced Mn²⁺ entry by TG treatment.These results suggest that PKC may modulate capacitative Ca²⁺ entry in BA cells.In the presence of extracellular Ca²⁺, TG enhanced cortisol production in BA cells.Calphostin C attenuated the TG-induced steroidogenesis dose-dependently(0.25-1μM).PMA enhanced the steroidogenesis dose-dependently(1-100nM).These results suggested that PKC may have a modulatory effect on the capacitative Ca²⁺ entry that links to steroidogenesis in BA cells.