title: Apparent histological changes of adipocytes after treatment with CL 316,243, a β-3-adrenergic receptor agonist.
abstract: OBJECTIVE
  The objective of this experiment was to study the effect of CL 316,243 (CL) (a highly selective β3-adrenergic receptor agonist) on cellular changes occurring in retroperitoneal white adipose tissue (RWAT) of lean and obese rats.
  
  
  METHODS
  Ten-month-old lean and obese Zucker rats were implanted subcutaneously with osmotic mini-pumps, infusing either saline or CL (1 mg/kg body weight/day) for 4 weeks.
  
  
  RESULTS
  There was no effect of CL on food intake. However, the resting metabolic rate in lean and obese rats increased by 55% and 96% per rat, respectively. Total RWAT weight decreased in both lean and obese rats under influence of CL treatment by 65% and 38%, respectively. Total body weight and body fat were lower in CL treated rats. Detection of uncoupling protein 1 (UCP1) in RWAT was confirmed qualitatively by both immunohistochemistry and immunofluorescence using a rabbit anti rat UCP1 antibody which showed the appearance of a marked increase of this protein in the adipose tissue. Stained semi-thin sections (0.5 μm) also demonstrated abundant nuclei in multilocular adipocytes, in endothelial cells associated with the vasculature, and in interstitial cells. In CL-treated obese rats, a clustering of several multilocular cells around the periphery of a white adipocyte was seen.
  
  
  CONCLUSIONS
  These results indicate that treatment of both lean and obese Zucker rats with CL induces extensive remodeling of RWAT that includes shrinkage of white adipose tissue, appearance of abundant multilocular cells in RWAT together with the appearance of a marked increase of UCP, preferentially in lean rats.
authors.affiliation: Research and Development Department, Pasteur Institute of Iran, Tehran, Iran ; Department of Biochemistry, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Masoud
authors.initials: M
authors.lastname: Ghorbani
authors.affiliation: Department of Medical Genetics, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Shahram
authors.initials: S
authors.lastname: Teimourian
authors.affiliation: Department of Animal Science, Pasteur Institute of Iran, Research and Production Complex, Karaj, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Farzad
authors.affiliation: Department of Animal Science, Pasteur Institute of Iran, Research and Production Complex, Karaj, Iran.
authors.forename: Nabiollah Namvar
authors.initials: NN
authors.lastname: Asl
mesh_terms: D017667:Adipocytes / Q000187:drug effects* / Q000473:pathology; D058667:Adrenergic beta-3 Receptor Agonists / Q000494:pharmacology*; D000818:Animals; D004149:Dioxoles / Q000494:pharmacology*; D015394:Molecular Structure; D011817:Rabbits; D051381:Rats; D011924:Rats, Zucker; D022702:Receptors, Adrenergic, beta-3 / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D058667:Adrenergic beta-3 Receptor Agonists; D004149:Dioxoles; D022702:Receptors, Adrenergic, beta-3; C076126:disodium (R,R)-5-(2-((2-(3-chlorophenyl)-2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2,3-dicarboxylate
keywords: Zucker rats; brown adipose tissue; cellularity of adipose tissue; obesity; thermogenesis; uncoupling protein