Role of peripheral serotonin in glucose and lipid metabolism

Purpose of review: Two independent serotonin systems exist, one in the brain and the other in the periphery. Serotonin is a well known monoaminergic neurotransmitter in the central nervous system and it is known to regulate feeding behavior, meal size, and body weight. On the other hand, there is much less evidence for the role of serotonin as a gastrointestinal hormone, particularly with respect to its effects on glucose and lipid metabolism. This review summarizes our current understanding of the role of peripheral serotonin on glucose and lipid metabolism and the implications of this for further research. Recent findings: The enterochromaffin cells of the gastrointestinal tract produce peripheral serotonin postprandially. In mice, it induces a decrease in the concentration of circulating lipids as well as hyperglycemia and hyperinsulinemia through its action on several serotonin receptors. Further, serotonin metabolites act as endogenous agonists for peroxisome proliferator-activated receptor ? and serotonin accelerates adipocyte differentiation via serotonin receptor 2A and 2C. Studies of serotonin are likely to provide new insights into the field of lipid accumulation and metabolism. Summary: Recent studies show new physiological functions of peripheral serotonin, linked to glucose and lipid metabolism. Peripheral serotonin may serve as an attractive new therapeutic target for the treatment of metabolic disorders in the near future.