Relation between fibroblast growth factor-21, adiposity, metabolism, and weight reduction.

Fibroblast growth factor-21 (FGF-21) has been proposed as a novel metabolic regulator, and animal experiments suggested that FGF-21 may affect energy balance. In humans, FGF-21 was correlated with obesity. Until now, no data exist regarding the relationship of FGF-21 and weight reduction in humans. We therefore investigated whether FGF-21 is modified by a moderate intended weight loss in a human trial. Thirty obese individuals (24 female, 6 male) participated in a weight reduction program for 6 months. In addition to several anthropometric and metabolic parameters, FGF-21 was measured before and after weight loss. Baseline serum FGF-21 was independently associated with markers of lipid metabolism and waist circumference. The multimodal intervention induced a moderate weight loss (97.4 ± 3.1 vs 92.2 ± 3.1 kg, P < .001), which was accompanied by a significant improvement of lipid and glucose metabolism. However, FGF-21 levels were not modified by moderate weight reduction; and FGF-21 levels at baseline were not a predictive marker for subsequent weight loss. The results presented here confirmed that FGF-21 levels are associated with markers of lipid metabolism and an estimate of abdominal adiposity. The finding that moderate weight loss did not induce changes of FGF-21 levels in humans suggests that FGF-21 is not directly regulated by fat mass under those conditions.