Comparative drug influence on peroxide mediated increase of cytosolic calcium in human endothelial cells.

The increase of cytosolic free calcium in human umbilical vein endothelial cells caused by peroxides was used as a model to determine and compare the putative cytoprotective properties of substances known to interfere with the generation or metabolism of reactive oxygen species. Hydrophilic hydrogen peroxide and lipophilic cumene hydroperoxide were used as sources of reactive oxygen. [Ca2+]i in endothelial cells was measured by the FURA method and the resting level was found to be 129.3 +/- 14.1 nM. Both peroxides were found to increase cytosolic calcium with dependence on the concentration and on the presence of extracellular calcium. Among the substances tested, only catalase and N-acetyl-cysteine were able to exhibit a significant cytoprotective effect.