Following the discovery of secretin in 1902, a host of further peptide hormones that are synthesised
and released from the gastrointestinal tract have been identified. While their roles in the regulation
of gastrointestinal function have been known for some time, it is now evident that many of these
hormones also physiologically regulate energy balance. Our understanding of how gut hormones
signal to the brain has advanced significantly in recent years. Several hormones, including peptide
YY, pancreatic polypeptide, oxyntomodulin, glucagon-like peptide 1 and cholecystokinin function as
satiety signals. In contrast, only ghrelin, produced by the stomach, has emerged as a putative hunger
signal, appearing to act both as a meal initiator and a long-term body weight regulator. Recent
research suggests that gut hormones can be manipulated to regulate energy balance in man
and that obese subjects retain sensitivity to the actions of gut hormones. The worldwide obesity
pandemic continues unabated, despite public health initiatives and current best therapy. Future
gut hormone-based therapies may provide an effective and well-tolerated treatment for obesity.
