Enteroendocrine hormones - central effects on behavior.

A number of appetite-regulating gut hormones alter behaviors linked to reward, anxiety/mood, memory and cognitive function, although for some of these (notably GLP-1 and CCK) the endogenous signal may be CNS-derived. From a physiological perspective it seems likely that these hormones, whose secretion is altered by nutritional status and by bariatric weight loss surgery, orchestrate neurobiological effects that are integrated and linked to feeding/metabolic control. Consistent with a role in hunger and meal initiation, ghrelin increases motivated behavior for food and, when food is not readily available, decreases behaviors in anxiety tests that would otherwise hinder the animal from finding food. Of the many anorexigenic signals, GLP-1 and PYY have been linked to a suppressed reward function and CCK (and possibly GLP-1) to increased anxiety-like behavior.