title: Decreased white fat cell thermogenesis in obese individuals.
abstract: OBJECTIVE
  To investigate whether white adipocyte thermogenesis and energy metabolism are reduced in obese individuals.
  
  
  METHODS
  Eight lean and 15 obese men and women; BMI 19-41.
  
  
  METHODS
  Isolated subcutaneous adipocytes were maintained in agarose gel for 20h under basal conditions and subsequently for 10h after stimulation with 1 microM isoprenaline. Direct microcalorimetry was performed continuously over 30h while biochemical measures were obtained after 0, 20, 25 and 30h.
  
  
  METHODS
  Total cellular thermogenesis, oxygen consumption, glycolysis, lipolysis, triglyceride/FFA substrate cycle, adenine nucleotides, DNA content as basis of reference.
  
  
  RESULTS
  Under basal and stimulated conditions, thermogenesis (5.6 and 8.6 microW/microgDNA, respectively; P < 0.0001) correlated negatively (P < 0.01 and P < 0.05, respectively) with the BMI and positively with O2 and glucose consumption, lactate, glycerol, FFA release and FFA re-esterification. Reduced basal lactate production with increased BMI (P < 0.05) indicates a more aerobic adipocyte metabolism in obese individuals. Negative correlation between BMI and stimulated triglyceride/FFA substrate cycle activity (P < 0.01) explains the decreased hormone induced adipocyte heat production in the obese.
  
  
  CONCLUSIONS
  The results suggest that a reduction of total body energy expenditure, which is discussed to cause obesity, can be associated with distinct metabolic alterations at a cellular level. However, since the estimated total body fat cell thermogenesis does not exceed 7% of the resting metabolic rate, the observed decrease of adipocyte heat production in the face of augmented BMI can only in part be responsible for the development of obesity.
authors.affiliation: University of Hohenheim, Institute for Biological Chemistry and Nutrition, Stuttgart, FRG Germany.
authors.forename: H
authors.initials: H
authors.lastname: Böttcher
authors.forename: P
authors.initials: P
authors.lastname: Fürst
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D001833:Body Temperature Regulation; D002151:Calorimetry; D002478:Cells, Cultured; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D005990:Glycerol / Q000378:metabolism; D006019:Glycolysis; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D019344:Lactic Acid / Q000378:metabolism; D008066:Lipolysis; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010101:Oxygen Consumption; D013566:Sympathomimetics / Q000494:pharmacology
chemical_list: D005230:Fatty Acids, Nonesterified; D013566:Sympathomimetics; D019344:Lactic Acid; D007545:Isoproterenol; D005990:Glycerol