title: Citrulline induces fatty acid release selectively in visceral adipose tissue from old rats.
abstract: METHODS
  During aging, increased visceral adipose tissue (AT) mass may result in impaired metabolic status. A citrulline (CIT)-supplemented diet reduces AT mass in old rats. We hypothesized that CIT could directly affect fatty acid (FA) metabolism in retroperitoneal AT.
  
  
  RESULTS
  A 24-h exposure of AT explants from old (25 months) rats to 2.5 mM CIT induced a 50% rise in glycerol and FA release, which was not observed in explants from young (2 months) animals. The phosphorylated form of hormone-sensitive lipase, a key lipolytic enzyme, was 1.5-fold higher in CIT-treated explants from old and young rats, whereas glyceroneogenesis, that provides glycerol-3P requested for FA re-esterification, and its key enzyme phosphoenolpyruvate carboxykinase, were down-regulated 40-70%. Specifically in young rats, beta-oxidation capacity and gene expressions of carnitine palmitoyl transferase 1-b and very long chain acyl-CoA dehydrogenase were strongly up-regulated by CIT. In contrast, in old rats, while glyceroneogenesis was lower, beta-oxidation was not affected, enabling increased FA release.
  
  
  CONCLUSIONS
  Hence, in visceral AT, CIT exerts a specific induction of the beta-oxidation capacity in young rats and a selective stimulation of FA release in old rats, therefore providing a direct mechanism of CIT action to reduce AT mass.
authors.affiliation: Université Paris Descartes, Sorbonne Paris Cité, France; Institut National de la Santé et de la Recherche Médicale UMR-S 1124, Faculté des Sciences Fondamentales et Biomédicales, Pharmacologie Toxicologie et Signalisation Cellulaire, Paris, France.
authors.forename: Nolwenn
authors.initials: N
authors.lastname: Joffin
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Jaubert
authors.forename: Sylvie
authors.initials: S
authors.lastname: Durant
authors.forename: Jean
authors.initials: J
authors.lastname: Bastin
authors.forename: Jean-Pascal
authors.initials: JP
authors.lastname: De Bandt
authors.forename: Luc
authors.initials: L
authors.lastname: Cynober
authors.forename: Christophe
authors.initials: C
authors.lastname: Moinard
authors.forename: Claude
authors.initials: C
authors.lastname: Forest
authors.forename: Philippe
authors.initials: P
authors.lastname: Noirez
mesh_terms: D017667:Adipocytes / Q000187:drug effects; D000367:Age Factors; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics; D002478:Cells, Cultured; D002956:Citrulline / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D007249:Inflammation / Q000235:genetics; D050152:Intra-Abdominal Fat / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D009924:Organ Culture Techniques; D010084:Oxidation-Reduction; D047495:PPAR gamma / Q000235:genetics; D017207:Rats, Sprague-Dawley
chemical_list: D005227:Fatty Acids; D047495:PPAR gamma; D002956:Citrulline; D002334:Carnitine O-Palmitoyltransferase
keywords: Adipose tissue; Aging; Citrulline; Fatty acids; Glyceroneogenesis