The concept of the gut as an endocrine organ is hardly a new. The gut peptide secretin
was the first substance to be termed a hormone whilst the appetite inhibitory actions
of cholecystokinin (CCK) were first reported over 30 years ago. However, in
recent years, further scientific endeavour in this field has been motivated by the need
to develop new strategies to tackle the global pandemic of obesity.
The prevalence of obesity in adults has increased by over 75% worldwide since
1980. Given that obesity is causally associated with cardiovascular disease, type 2 diabetes,
hypertension, stroke, obstructive sleep apnoea and certain cancers, this has
translated into healthcare costs of over half a billion pounds every year in the UK
alone. Obesity is not only a problem in the developed world, but is set to overtake
infectious diseases as the most significant contributor to ill-health worldwide and has
been classified as an epidemic by the World Health Organization .
166 Wren
Public health initiatives have failed to reverse the rising incidence of obesity.
Medical and behavioural interventions, with the exception of bariatric surgery, have
limited success, as discussed in the treatment section of this volume. This chapter will
focus on the peptide hormone signals from the gut that communicate the status of
body energy stores to the brain and the brain centres on which they act. These regulatory
systems are not only of academic interest, but are likely to underpin any future
strategy to tackle obesity, by providing drug targets for the holy grail of safe sustainable
weight loss.
