Energy requirement for the maintenance of membrane potential in rat liver cells in situ.

The transmembrane potential of female rat liver cells in situ was-52.4 mV. This was decreased to -42.9 mV by ethacrynic acid (4 mg/100 g), but not by ouabain (1 mg). DL-Ethionine (25-100 mg) caused a decrease in the membrane potential and tissue ATP content. A high dose ethionine (100 mg) increased tissue Na content and decreased K content. By applying adenine (25 mg) to the animals treated with ethionine (100 mg), the membrane potential, ATP content and K content were increased and the Na content was decreased. The repolarized membrane potential in the animals treated with adenine following the ethionine was again depolarized by the administration of ouabain, but not by the administration of ethacrynic acid. These results suggest that two kinds of active ion transport mechanisms, ethacrynic acid-sensitive and ouabain-sensitive mechanisms, may be involved in maintenance of the membrane potential of rat liver cells.