Uptake of quaternary ammonium compounds into rat liver plasma membrane vesicles

In order to elucidate the mechanism by which quaternary ammonium compounds are transported across the rat hepatocyte plasma membrane, the transport of five quaternary ammonium compounds through rat hepatocyte plasma membrane vesicles was investigated. Transport is only observed when the organic cations possess a high lipophilicity. Uptake appeared to be a passive process and was not stimulated by a transmembrane electrical potential difference nor by the presence of an excess of anions like I-. Taurocholate decreased the uptake. However in the presence of a catalytic amount of tetraphenylborate a transmembrane electrical potential difference (inside negative) stimulated the uptake.