O'Sullivan A J, Jamieson J D
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.
Biochem J. 1992 Jul 15;285 ( Pt 2)(Pt 2):597-601. doi: 10.1042/bj2850597.
The effect of protein kinase C (PKC) on amylase discharge from streptolysin-O-permeabilized rat pancreatic acini was investigated. Addition of phorbol 12-myristate 13-acetate (PMA) to permeabilized cells potentiated Ca(2+)-stimulated release, but had no effect on discharge at non-stimulatory Ca2+ concentrations. PMA markedly shifted the Ca(2+)-concentration-dependence of amylase discharge to the left, by enhancing the time over which the permeabilized cells release. This effect was inhibited by both staurosporine and PKC-19-31-amide peptide inhibitor, indicating that the effect of PMA was due to its action on PKC. Staurosporine also partially inhibited amylase release at the optimal concentration of Ca2+; this effect was not replicated by the more specific PKC-19-31-amide peptide inhibitor and may be due to an effect on another second-messenger system. PKC appears to be an important modulator of release in pancreatic acini, but its activation is not an absolute requirement for Ca(2+)-dependent amylase discharge.
研究了蛋白激酶C（PKC）对经链球菌溶血素-O通透处理的大鼠胰腺腺泡淀粉酶分泌的影响。向通透处理的细胞中添加佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA）可增强Ca(2+)刺激的释放，但在非刺激Ca2+浓度下对分泌无影响。PMA通过延长通透处理细胞的释放时间，使淀粉酶分泌的Ca(2+)浓度依赖性显著向左移动。这种效应被星形孢菌素和PKC-19-31酰胺肽抑制剂所抑制，表明PMA的作用是由于其对PKC的作用。在最佳Ca2+浓度下，星形孢菌素也部分抑制淀粉酶释放；更具特异性的PKC-19-31酰胺肽抑制剂未重现这种效应，这可能是由于对另一种第二信使系统的作用。PKC似乎是胰腺腺泡释放的重要调节因子，但其激活并非Ca(2+)依赖性淀粉酶分泌的绝对必要条件。
