Is there a role for the liver in the control of food intake?

The liver, despite its key place in energy regulation, has been implicated in feeding for only the last 20 yr and this theory is still quite controversial. Information about liver metabolism is transmitted to areas in the brain which receive other information relevant to feeding such as from gustatory and central glucoreceptors. Behavioral studies of feeding in which nutrients or antimetabolites have been infused into the liver are equivocal. However, if one considers the liver as acting in concert with oral factors and the gastrointestinal tract, its role in feeding becomes clearer. Glucose infusion into the liver or oral intake of glucose have small effects on glucose intake by themselves. Combined, these two manipulations interact giving reliable suppression of subsequent glucose intake. Fructose when given peripherally is not metabolized by the brain but is by the liver and can suppress feeding. These and other considerations suggest that the liver is probably important in controlling feeding as part of a sequence of integrated events beginning in the mouth, integrated by the brain, and ending with the appropriate behaviors.