Effects of hematoporphyrin derivative and light on Y79 retinoblastoma cells in vitro.

Retinoblastoma Y79 cells exposed to a hematoporphyrin derivative and light were examined with regard to the production of intracellular lipid peroxide and morphologic changes, in the presence or absence of oxygen. The intracellular lipid peroxide was related to the dose of hematoporphyrin derivative and the duration of photoradiation, under aerobic conditions. The formation of lipid peroxide was not inhibited with superoxide dismutase and catalase, but it was inhibited with mannitol and 1,4-diazabicyclo[2,2,2]octane, which were inhibitors of hydroxyl radicals and singlet oxygen, respectively. The mitochondria were apparently the target organelle in Y79 retinoblastoma cells.