PENETRATION, DISTRIBUTION AND EFFECTS OF [C-14] PENTACHLOROPHENOL INSIDE CULTURED ACER CELLS

Suspension cultures of Acer pseudoplatanus cambium cells (Lamport's strain) were killed by pentachlorophenol at concentrations around 70 nmol mg-1 cell protein. The fact that PCP penetrates the cells is shown by the readily induced uncoupling effect on mitochondria inside the cells. The full uncoupling effect was obtained in the cells at a concentration of 17.5 nmol PCP mg-1 cellular protein. This effect is probably, in itself, the main cause of cell death. Binding of [C-14]PCP to the cells could be seen to take place almost instantaneously, and variations in the concentration of PCP had no effect on the proportion of PCP observed to be bound to the cells ca 90 +/- 5%) and that which was free in the medium. The presence of p-chloromercuribenzenesulphonate (100-mu-M) was without effect on this ratio. No saturable target could be seen, in the range of concentrations studied here. With the help of electron microscopic studies, it was postulated that the PCP was distributed between the lipid and water fractions of the cell. The membrane concentration of PCP, able to induce full uncoupling, was estimated to be ca 13.5 mM and the value of the log of the membrane/water partition coefficient, evaluated in the same way as log P (octanol/water partition coefficient), to be ca 4.13.