Alterations of hormonally active fibroblast growth factors after Roux-en-Y gastric bypass surgery.

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.