title: Serum visfatin concentrations are positively correlated with serum triacylglycerols and down-regulated by overfeeding in healthy young men.
abstract: BACKGROUND
  Visfatin is an insulin-mimicking adipokine. Visfatin is elevated in obesity and type 2 diabetes. However, its role in glucose and lipid metabolism in healthy humans is unclear.
  
  
  OBJECTIVE
  The objective was to investigate the correlations of visfatin with phenotypes of glucose, lipids, and body composition and the responses of visfatin to short-term overfeeding in healthy young men.
  
  
  METHODS
  Sixty-one healthy young men were recruited from the Newfoundland population. Serum visfatin, interleukin 6, glucose, insulin, total cholesterol, HDL cholesterol, LDL cholesterol, and triacylglycerol concentrations were measured with an autoanalyzer, and percentage body fat (%BF) and percentage trunk fat (%TF) were measured with dual-energy X-ray absorptiometry. Insulin resistance and beta cell function were assessed with the homeostasis model. All measurements were completed at baseline and after a 7-d overfeeding protocol exceeding the baseline requirement by 70%. Subjects were classified on the basis of %BF as lean (<21%), overweight (21-25.9%), or obese (>or=26%).
  
  
  RESULTS
  Multiple regression analysis showed that triacylglycerols correlated with fasting serum visfatin (P < 0.001). Moreover, serum visfatin decreased 19% overall-23% in lean, 9% in overweight, and 18% in obese subjects (P < 0.0001)-after the overfeeding protocol. None of the variables measured, including interleukin 6, were associated with the reduction in visfatin. In contrast with the findings in mice, visfatin concentrations before and after overfeeding did not correlate with glucose, insulin, insulin resistance, beta cell function, %BF, or %TF.
  
  
  CONCLUSIONS
  Visfatin is down-regulated by overfeeding. Under physiologic conditions, visfatin does not appear to control glucose metabolism but may play a regulatory role in lipid metabolism.
authors.affiliation: Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St John's, NL, Canada. gsun@mun.ca
authors.forename: Guang
authors.initials: G
authors.lastname: Sun
authors.forename: Jessica
authors.initials: J
authors.lastname: Bishop
authors.forename: Sammy
authors.initials: S
authors.lastname: Khalili
authors.forename: Sudesh
authors.initials: S
authors.lastname: Vasdev
authors.forename: Vicki
authors.initials: V
authors.lastname: Gill
authors.forename: David
authors.initials: D
authors.lastname: Pace
authors.forename: Donald
authors.initials: D
authors.lastname: Fitzpatrick
authors.forename: Edward
authors.initials: E
authors.lastname: Randell
authors.forename: Ya-Gang
authors.initials: YG
authors.lastname: Xie
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
mesh_terms: D016207:Cytokines / Q000097:blood* / Q000378:metabolism; D004032:Diet; D015536:Down-Regulation; D002149:Energy Intake / Q000502:physiology*; D006801:Humans; D008297:Male; D054409:Nicotinamide Phosphoribosyltransferase; D014280:Triglycerides / Q000097:blood* / Q000378:metabolism
chemical_list: D016207:Cytokines; D014280:Triglycerides; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human