Effects of rosiglitazone on fasting plasma fibroblast growth factor-21 levels in patients with type 2 diabetes mellitus

Objective: Fibroblast growth factor-21 (FGF-21) has recently been characterized as a potent metabolic regulator, but its pathophysiologic roles in humans remain unknown. This study aimed to investigate the effects of rosiglitazone on plasma FGF-21 levels in patients with type 2 diabetes mellitus (T2DM). Design and methods: Thirty patients with new-onset T2DM (nT2DM), 34 type 2 diabetic patients with poor glycemic control (pT2DM) after the treatment with single hypoglycemic agent metformin, and 30 sex- and age-matched normal glycaemic controls (NGT) participated in the study. The pT2DM group was treated with rosiglitazone for 12 weeks. Plasma FGF-21 levels were measured with a RIA. The relationship between plasma FGF-21 levels and metabolic parameters was also analyzed. Results: Fasting plasma FGF-21 levels were higher in nT2DM and pT2DM groups than in the control (1.81±0.64 vs 1.87±0.63 vs 1.52±0.61 μg/l, P<0.05), but there was no difference between nT2DM and pT2DM groups. Fasting plasma FGF-21 levels were decreased significantly in pT2DM group after the treatment with rosiglitazone compared with pre-treatment (1.59±0.63 vs 1.87±0.64 μ/l, P<0.05). In all diabetic patients, multiple regression analysis showed that HbA1c, fasting insulin, and homeostasis model assessment-insulin resistance index were independently associated with plasma FGF-21 levels. Conclusions: In pT2DM patients, plasma FGF-21 levels are increased, but significantly decreased after the treatment with rosiglitazone on top of ongoing metformin therapy. These data suggest that rosiglitazone may play a role in lowering FGF-21 levels in T2DM patients.