[Mechanism of cell damage by hematoporphyrin derivative (HPD) plus light. II. Effect of HPD plus light on respiration and oxidative phosphorylation in hepatoma cells and normal liver mitochondria].

The effects of HPD plus light on energy metabolism and membrane structure of hepatoma cell and normal liver mitochondria were investigated. HPD was bound to mitochondria either in vitro or in vivo. Mitochondria bound HPD plus light increased MDA level, decreased respiratory intensity and respiratory control, dissociated phosphorylation from oxidation and enhanced mitochondria swelling on age. These effects were related to HPD concentration and exposure time but it was unchanged in the control. These results showed that the loss of function of oxidation phosphorylation was due to the mitochondrial membrane system damage under the action of singlet oxygen produced by HPD bound mitochondria following light activation.