HEMATOPORPHYRIN DERIVATIVE (PHOTOFRIN((R))) PHOTODYNAMIC-ACTION ON CA2+ TRANSPORT IN MONKEY KIDNEY-CELLS (CV-1)

After 24 h incubation with Photofrin(R) (PF), photodynamic action has been studied on Ca2+ transport in CV-1 cells. A moderate increase of the cytosolic free Ca2+ concentration [Ca2+](i) is observed immediately after a dose of irradiation which yields a survival rate of less than 5% at 48 h. In parallel, studies on digitonin-permeabilized cells indicate that such a treatment inhibits endoplasmic reticulum Ca2+ uptake with few alterations of this process in mitochondria. In contrast, ADP-stimulated respiration is impeded and intracellular ATP level decreases. It is suggested that direct damage to endoplasmic reticulum as well as mitochondrial disturbance are the primary mechanisms responsible for a nontransient elevation of[Ca2+](i) preceding cell death.