PHOTODYNAMIC EFFICIENCY OF PROTOPORPHYRIN-IX - COMPARISON OF ENDOGENOUS PROTOPORPHYRIN-IX INDUCED BY 5-AMINOLEVULINIC ACID AND EXOGENOUS PORPHYRIN-IX

Photodynamic efficiency of protoporphyrin IX (PP) accumulated in HeLa cells by the incubation of PP with HeLa cells was compared with that o f accumulated PP formed from 5-aminolevulinic acid (ALA) as a precurso r. The ALA-induced PP was photodynamically more efficient than exogeno us PP. The difference is caused by monomeric PP concentration and PP l ocalization site in HeLa cells. Exogenous PP was accumulated mainly in plasma membrane, and the membrane was strongly damaged by irradiation . The ALA-induced PP was selectively accumulated in mitochondria and i nactivated the mitochondrial function by irradiation.