title: In Vitro lipolysis is associated with whole-body lipid oxidation and weight gain in humans.
abstract: To assess the association of adipocyte size with cellular lipolysis and between cellular lipolysis and whole-body lipid oxidation. This study also assessed the association between adipocyte size and cellular lipolysis with weight and fat mass gain.
  
  
  
  Subjects had assessment of percent body fat (%fat) and adipose tissue biopsy for in vitro lipolysis (n = 325), and a subset of subjects had measurement of whole-body lipid oxidation (n = 112). A subset of subjects (n = 243) returned for repeated measurements of body weight and composition (mean follow-up 8.2 ± 5.5 years).
  
  
  
  In vitro lipolysis (r = 0.47, P < 0.0001) and adipocyte size (r = 0.49, P < 0.0001) were strongly associated with %fat. In vitro lipolysis (P = 0.04) but not adipocyte size (P = 0.44) was associated with whole-body fat oxidation. Adipocyte size was not associated with rate of percent weight gain (P = 0.20) but was negatively associated with rate of percent fat mass gain (P = 0.01). In vitro lipolysis was negatively associated with rate of percent weight gain (P = 0.02) and had a marginal negative association with rate of percent fat mass gain (P = 0.08).
  
  
  
  These results indicate inherent characteristics of adipocytes, including size and lipolytic activity, may be important determinants of whole-body lipid oxidation and subsequent weight gain.
authors.affiliation: Obesity and Diabetes Clinical Research Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, USA.|University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: Joseph
authors.identifier: 0000-0002-0156-3150
authors.initials: J
authors.lastname: Frankl
authors.affiliation: University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: Paolo
authors.identifier: 0000-0003-2774-9161
authors.initials: P
authors.lastname: Piaggi
authors.affiliation: University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Foley
authors.affiliation: University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Krakoff
authors.affiliation: University of Arizona College of Medicine, Tucson, Arizona, USA.
authors.forename: Susanne B
authors.initials: SB
authors.lastname: Votruba
mesh_terms: D017667:Adipocytes / Q000166:cytology*; D000328:Adult; D001823:Body Composition; D001835:Body Weight; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008066:Lipolysis / Q000502:physiology*; D008297:Male; D010084:Oxidation-Reduction; D015430:Weight Gain; D055815:Young Adult