Interactions between porphyrins and mitochondrial benzodiazepine receptors.

Dicarboxylic porphyrins were reported to be potent inhibitors of the binding of benzodiazepines to peripheral drug receptors in mitochondria, but the reverse does not appear to be true. Moreover, the photosensitization of mitochondria by the tumor-localizing porphyrin dimer/oligomer fraction of 'HPD' was not inhibited by benzodiazepines in cell culture.