Liver denervation does not modify feeding responses to metabolic challenges or hypertonic NaCl induced water consumption

Following liver denervation (LD) food intake (FI) and body weights of the LD rats did not vary significantly from sham operated animals (S). Rats were injected intraperitoneally at 0800 hr (light/dark, 12:12, lights off 1230 hr) with saline (SAL), 2-deoxy-d-glucose (2DG): Experiment (EXP) 1, 250 and 400 mg/kg; EXP 2, 100 and 150 mg/kg and insulin: EXP 1, 6 and 12 IU/kg; EXP 2, 0.75 and 1.5 IU/kg. Both LD and S rats increased their FI similarly over SAL following 2DG and insulin. In EXP 1 rats were also injected with glucagon (G) (540 micrograms/kg) or SAL at 1330 hr. While this dose of G was later shown to cause hyperglycemia no suppression of FI was noted in either group. Later these rats were injected at 0800 hr with (10 ml/kg) SAL or hypertonic NaCl (0.25 M, 0.5 M and 1.0 M). The two highest doses elevated water intake of both groups comparably. In EXP 2 the ad lib chow fed rats were injected with G (540 and 800 micrograms/kg) or SAL prior to a one hour presentation of a milk diet at 0800 hr. In both groups, after G, meal size and length were significantly and similarly reduced. The data reveal no deficits in the LD rats' response to metabolic and hypertonic NaCl challenges and question what role, if any, liver glucoreceptors have on feeding behavior and liver osmotic receptors have on hypertonic NaCl induced water consumption.