BackgroundObesity is a result of a relative excess in energy intake over energy expenditure. These processes are controlled by genetic, environmental, psychological and biological factors. One of the factors involved in the regulation of food intake and satiety is dopaminergic signalling. A small number of studies have reported that striatal dopamine D2/D3 receptor [D2/3R] availability is lower in morbidly obese subjects.MethodsTo confirm the role of D2/3R in obesity, we measured striatal D2/3R availability, using [123I]IBZM SPECT, in 15 obese women and 15 non-obese controls.ResultsStriatal D2/3R availability was 23% (p = 0.028) lower in obese compared with non-obese women.ConclusionThis study is an independent replication of the finding that severely obese subjects have lower striatal D2/3R availability. Our findings invigorate the evidence for lower striatal D2/3R availability in obesity and confirm the role of the striatal dopaminergic reward system in obesity.

The DJBL is a safe and effective alternative to invasive bariatric procedures. Six months of DJBL treatment combined with diet leads to superior weight loss and improvement of T2DM when compared with diet alone.

Thirty-five morbidly obese patients underwent Roux-en-Y gastric bypass surgery (RYGB). In addition to weight loss, these patients showed significant improvement of insulin resistance and a reduction of hepatic fat content. Three months after surgery, the serum bile salts were slightly but significantly elevated, and the levels of the endocrine-acting fibroblast growth factor 19 (FGF19) and FGF21 were increased. FGF19 and FGF21 play a role as regulators of hepatic lipid and glucose metabolism. These results show that RYGB surgery improves metabolism and that this improvement is still apparent 3 months after surgery. Bile salts may play a key role in the improvement of metabolism after RYGB. Why serum bile salt concentrations are elevated after RYGB needs to be investigated.

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These data indicate that deterioration of glucose metabolism in T2DM is associated with a decline of GLP-1 levels. Calorie restriction facilitates glucose metabolism and blunts hyperinsulinemia in obese (diabetic) humans. Additional duodenal exclusion through RYGB induces gut hormone release and hyperinsulinemia but does not improve postprandial glucose levels any further. Our data thus strongly suggest that calorie restriction underlies the short-term metabolic benefits of RYGB in obese T2DM patients.