CA2+ INFLUX INITIATES DEATH OF HEPATOCYTES INJURED BY ACTIVATION OF COMPLEMENT

To clarify the role of cytosolic Ca2+ in hepatocellular death, we expo sed cultured hepatocytes to human serum and a monoclonal antibody dire cted against rat liver plasma membranes to produce complement-mediated cell injury. The change in cytosolic Ca2+ concentration was measured by fura2 and fluo3 fluorescence. With the addition of monoclonal antib ody, an increase in cytosolic Ca2+ was observed, followed by cell deat h. Both the increase in intracellular Ca2+ and cell death were prevent ed by intracellular Ca2+ chelation or removal of extracellular Ca2+. W e conclude that an increase in cytosolic Ca2+ plays a major role in he patocellular injury induced by exposure of the cell membrane to monocl onal antibody.