Circadian effects of hepatic branch vagotomy on the feeding response to 2-deoxy-D-glucose in rats.

The influence of hepatic branch vagotomy (HBV) in comparison to sham-vagotomy (SV) on the hyperphagia induced in rats by intraperitoneally injected 2-deoxy-D-glucose (2-DG, 250 mg/kg b.wt.) was investigated in nine experiments. Injections were given at various times of the 12-h light/12-h dark cycle in ad libitum fed rats (0 h, 1 h, 2 h, 4 h, 10 h after dark onset; 0 h and 6 h after onset of the bright phase). In two further experiments, 2-DG was injected 1 h after the onset of darkness or at the onset of light immediately after a meal (duration: 30 min) induced by short-term (2 h) food deprivation. 2-DG significantly increased food intake in SV-rats in all experiments, whereas in HBV rats there was no significant response to 2-DG in two experiments (injections 1 h after dark onset after ingestion of a meal, or 4 h after the onset of darkness). These findings indicate that an intact hepatic vagus branch is a prerequisite for "glucoprivic" feeding under certain conditions, and that hepatic vagal glucoreceptors participate in the control of feeding.