Effect of Microcystin-LR on Cultured Rat Endothelial Cells

Introduction: Microcystin-LR (MCLR), a cyclic heptapeptide synthesis ed by the cyanobacterium Microcystis aeruginosa induces hepatoxicity in many species including man. After administration to laboratory rodents, MCLR rapidly induces severe liver haemorrhage which is associated with centrilobular hepatocyte necrosis. MCLR not only induces the rapid onset of liver damage in rodents, but also induces necrosis of cultured rat hepatocytes. The mechanism by which MCLR induces hepatoxicity is not known. MCLR does, however, induce early changes in cultured hepatocytes, such as deformation of cells (blebbing) rapid rise in intracellular calcium, increased phoshorylase-a activity, depletion of glutathione, and the release of arachidonic acid metabolites. These early events are followed by the leakage of adenine nucleotides and cytosolic enzymes and eventually, the loss of cell viability. Pub. in Med. Sci. Res., v18 p241-244 1990.