title: Porphyrin-sensitized photodynamic damage of isolated rat liver mitochondria.
abstract: The respiration rates and the respiratory control ratios of isolated rat liver mitochondria have been measured following exposure to 0--160 kJ/m2 of near-ultraviolet radiation (blacklight) in the presence of low concentrations of porphyrins (0.1--0.2 mumol/l). Depending on the light dose, the concentration and the type of porphyrin, the following sequence of reactions occurred: uncoupling and inhibition of oxidative phosphorylation, energy dissipation, inhibition of respiration and swelling and disruption of the mitochondria. The detrimental effects could not be elicited in the absence of oxygen, neither could they be elicited by porphyrins or light alone. At equimolar concentrations, the effectiveness of the porphyrins as photosensitizers were: deuteroporphyrin greater than protoporphyrin much greater than coproporphyrin greater than uroporphyrin. The results may be of importance to explain the skin lesions seen when porphyrins of different hydrophobicity accumulate in the skin.
mesh_terms: D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004734:Energy Metabolism / Q000528:radiation effects; D008930:Mitochondria, Liver / Q000378:metabolism / Q000528:radiation effects*; D010101:Oxygen Consumption / Q000528:radiation effects; D011166:Porphyrins / Q000494:pharmacology*; D051381:Rats; D014466:Ultraviolet Rays
chemical_list: D011166:Porphyrins