Evidence for hepatic glucostatic regulation of food intake in the domestic chicken and its interaction with gastro-intestinal control.

1. Male birds of a laying strain had permanent catheters introduced into the hepatic portal vein via the coccygeo-mesenteric vein. 2. Infusions of 5 ml of 40, 100 or 150 g glucose/l solution over 2 min caused a non-significant depression of food intake compared with a 9 g NaCl/l control solution. 3. Infusions of a range of isotonic glucose solution (0 to 60 g glucose/l, 30- mosm) at 1.4 ml/min over 3 h caused food intake depression within the 3-h period (P less than 0.01) proportional to the logarithm of the dose. 4. This effect was not observed when 60 g glucose/l was infused at the above rates into the jugular vein. 5. Starvation of the bird for 21 h accentuated the depressive effect of glucose load on food intake, especially when birds were not given food until after the 3-h infusion. 6. The infusion of solutions of sodium chloride (1.0 to 13.0 g/l, 33 to 433 mosmoles/kg) at 1.4 ml/min over 3 h stimulated food intake within the range of 3 to 7 g NaCl/l (100 to 233 mosm) but suppressed intake outside this range. This can be interpreted as a possible interaction with water intake control. 7. Infusion of 20 ml of glucose solution (0, 18 or 54 g/l) over 5 min into the crop and 0, 3.75 or 60 g glucose/l at 1.4 ml/min over 3 h into the hepatic portal vein, caused an additive, linear depression of food intake.