[Effect of the alkylating agent Trenimon on the cell membrane]

The alkylating agent Trenimon (10(-9) mol/l - 10(-6) mol/l) caused characteristic changes in membrane polarization, in cell counts and in surface charge (zeta potential). After short incubation time this effect of Trenimon is particularly pronounced in terms of transmembrane potential (TMP), whereas a decrease in surface charge was found only after incubation times longer than 24 hours. Immediately after addition of the chemotherapeutic agent to the HeLa cells damped oscillation of the TMP was observed with amplitudes being a function of the concentration of the agent. For incubation times between 24 and 96 hours low concentration (10(-8) mol/l) entailed increase in membrane polarization. Membrane depolarization was enhanced at higher doses of 10(-7) mol/l and 10(-6) mol/l. After lengthy incubation time drastic depolarizations and decrease in surface charge were accompanied by morphological cell damage such as "giant cells" and "off spherical" cells. Grunicke et al. [4] also found after Trenimon administration changes in membrane function before the DNA synthesis was influenced. These observations indicate that the cell membrane can be considered as a direct point for the effect of the alkylating agent Trenimon.