Effects of phenols on growth rate and adenosine uptake of CHO cells

The use of Chinese hamster ovary (CHO) cells as a test system for predicting the toxicity of xenobiotics is described. Compared to eukaryotic microorganisms this system is two to three times more sensitive but needs more care in handling. In the study of the effects of various phenol derivatives on CHO cell growth and on an important functional membrane protein, the nucleoside transport system, a good correlation was observed. In addition, in both cases the effects correlated very well with the octanol/water partition coefficient, making quantitative structure-activity predictions possible. The results suggest that there is a common mechanism of action of these lipophilic xenobiotics. They are accumulated in the hydrophobic region of the lipid bilayer of the plasma membrane, where enzymes and transport systems are located, which are important for cell viability. These high concentrations of the chemicals lead to an inhibition of functional membrane proteins, with the consequence that cell growth stops.