Evidence for a role of the sodium pump of hepatocytes in the control of food intake.

To test the hypothesis that the sodium pump of hepatocytes is involved in the control of food intake, we investigated the effect of ouabain, an inhibitor of the sodium pump, on feeding in intact and hepatic vagotomized rats. Ouabain (2 mg/kg b.wt.), injected intraperitoneally during the bright phase of the lighting cycle, stimulated feeding in intact and sham-vagotomized rats, but not in hepatic vagotomized rats. Atropinization did not block ouabain's hyperphagic effect. Ouabain did not affect portal blood glucose level. Rats started to eat sooner than normal when ouabain was injected, while their meal size and duration was unchanged. The results are consistent with a role of the sodium pump of hepatocytes in the control of food intake.