title: Serum fibroblast growth factor 21 in human obesity: regulation by insulin infusion and relationship with glucose and lipid oxidation.
abstract: OBJECTIVE
  Fibroblast growth factor 21 (FGF21) reduces plasma glucose and triglycerides, and increases free fatty acid oxidation in animal models of diabetes. The aim of the present study was to assess the relationships of serum FGF21 with glucose oxidation (GOx) and lipid oxidation (LOx) in the baseline and insulin-stimulated conditions in lean and obese subjects.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Eighty-four subjects with normal glucose tolerance, 42 lean (body mass index (BMI) <25 kg m(-2)) and 42 overweight or obese (BMI between 25 and 40 kg m(-2)).
  
  
  METHODS
  Euglycemic hyperinsulinemic clamp and indirect calorimetry in the baseline state and during last 30 min of the clamp. The change in respiratory quotient (ΔRQ) in response to insulin was used as a measure of metabolic flexibility. Serum FGF21 was determined in the baseline state and after the clamp.
  
  
  RESULTS
  Obese subjects had higher LOx in the baseline and insulin-stimulated conditions, lower insulin-stimulated GOx and ΔRQ (all P<0.05). Fasting serum FGF21 did not differ between the groups. Insulin infusion resulted in an increase in serum FGF21 in the obese (P=0.0001), but not in the lean group (P=0.76). Postclamp serum FGF21 was higher in the obese subjects (P=0.0007). In this group, postclamp FGF21 was related to LOx during the clamp (r=0.32, P=0.044), change in GOx and LOx in response to insulin (r=-0.44, P=0.005; r=0.47, P=0.002; respectively) and ΔRQ (r=-0.50, P=0.001).
  
  
  CONCLUSIONS
  An increase in serum FGF21 in response to insulin in obese subjects might represent inappropriate response, possibly associated with metabolic inflexibility in obesity and insulin resistance.
authors: 1] Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Białystok, Białystok, Poland [2] Department of Prophylaxis of Metabolic Diseases, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland.
authors: M
authors: M
authors: Strączkowski
authors: M
authors: M
authors: Karczewska-Kupczewska
authors: A
authors: A
authors: Adamska
authors: E
authors: E
authors: Otziomek
authors: I
authors: I
authors: Kowalska
authors: A
authors: A
authors: Nikołajuk
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D003430:Cross-Sectional Studies; D005260:Female; D005346:Fibroblast Growth Factors / Q000097:blood* / Q000187:drug effects; D015309:Glucose Clamp Technique; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood* / Q000188:drug therapy; D010084:Oxidation-Reduction; D011237:Predictive Value of Tests; D013851:Thinness / Q000097:blood* / Q000188:drug therapy; D014280:Triglycerides / Q000097:blood*
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D008055:Lipids; D014280:Triglycerides; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors