Protein kinase C and parietal cell function.

Ca2+-phospholipid dependent protein kinase activity and the effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on H+ secretion was studied in guinea-pig parietal cells. In resting parietal cells PK-C activity was distributed almost equally in both the cytosolic and particulate cell fraction. Exposure of the cells to TPA resulted in a loss of cytosolic PK-C activity which was not accompanied by a concomitant increase of particulate activity. Furthermore TPA inhibits the K+/H+-ATPase and dissipates H+ gradient in intact gastric vesicles by a protonophoric action. The role of these biochemical events for the antisecretory action of TPA found in the intact parietal cell are discussed.