Differences in membrane ion transport between hepatocytes from the periportal and the pericentral areas of the liver lobule

We studied the Na⁺/K⁺ pump, Na⁺/K⁺ ATPase activity, and oxygen consumption (QO₂) in hepatocytes isolated from the periportal (PH) and pericentral (CH) regions of the liver lobule, to provide an insight into the functional properties of these cells. Na⁺/K⁺ pump activity was determined using⁸⁶Rb⁺ (a functional analog of K⁺) and ouabain, a specific inhibitor of this transport system. Our results indicate the the Na⁺/K⁺, pump and Na⁺/K⁺ ATPase activity are significantly lower in CH than in PH, although basal ouabain-sensitive (OS) QO₂ was negligible in both of these cell preparations. However, OSQO₂ was significantly lower in CH than in PH when the Na⁺/K⁺ pump was activated using the ionophore nystatin in a Na⁺-containing medium. These results indicate that the differences in membrane ion transport exist between hepatocytes from different locations of the liver lobule.