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

After 24 h incubation with Photofrin(R) (PF), photodynamic action has been studied on Ca2+ transport in CV-1 cells. A moderate increase of t he 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 ind icate that such a treatment inhibits endoplasmic reticulum Ca2+ uptake with few alterations of this process in mitochondria. In contrast, AD P-stimulated respiration is impeded and intracellular ATP level decrea ses. It is suggested that direct damage to endoplasmic reticulum as we ll as mitochondrial disturbance are the primary mechanisms responsible for a nontransient elevation of[Ca2+](i) preceding cell death.