Photodynamic effects of hematoporphyrin-derivative on transmembrane transport systems of murine L929 fibroblasts.

Photodynamic treatment of murine L929 fibroblasts with hematoporphyrin-derivative causes deterioration of various membrane functions. Most sensitive to photodynamic inactivation are the energy-coupled transport systems for aminoisobutyric acid and for Rb+. The facilitated diffusion system for 2-deoxy-D-glucose is slightly less sensitive. After longer illumination periods also the membrane barrier function is impaired, as reflected by K+ leakage and increased passive Rb+ uptake. After still longer illumination periods intermolecular protein crosslinking can be observed. This makes it unlikely that intermolecular protein crosslinking is causally involved in the deterioration of these membrane functions.