title: Vitamin C inhibits leptin secretion and some glucose/lipid metabolic pathways in primary rat adipocytes.
abstract: Antioxidant-based treatments are emerging as an interesting approach to possibly counteract obesity fat accumulation complications, since this is accompanied by an increased systemic oxidative stress. The aim of this study was to analyze specific metabolic effects of vitamin C (VC) on epididymal primary rat adipocytes. Cells were isolated and incubated for 72 h in culture medium, in the absence or presence of 1.6 nM insulin, within a range of VC concentrations (5-1000 microM). Glucose- and lipid-related variables as well as the secretion/expression patterns of several obesity-related genes were assessed. It was observed that VC dose dependently inhibited glucose uptake and lactate production, and also reduced glycerol release in both control and insulin-treated cells. Also, VC caused a dramatic concentration-dependent fall in leptin secretion especially in insulin-stimulated cells. In addition, VC (200 microM) induced Cdkn1a and Casp8, partially inhibited Irs3, and together with insulin drastically reduced Gpdh (listed as Gpd1 in the MGI database) gene expressions. Finally, VC and insulin down-regulatory effects were observed on extracellular and intracellular reactive oxygen species production respectively. In summary, this experimental assay describes a specific effect of VC in isolated rat adipocytes on glucose and fat metabolism, and on the secretion/expression of important obesity-related proteins.
authors.affiliation: Department of Nutrition and Food Sciences, Physiology and Toxicology, University of Navarra, Pamplona, Spain.
authors.forename: D F
authors.initials: DF
authors.lastname: Garcia-Diaz
authors.forename: J
authors.initials: J
authors.lastname: Campion
authors.forename: F I
authors.initials: FI
authors.lastname: Milagro
authors.forename: N
authors.initials: N
authors.lastname: Boque
authors.forename: M J
authors.initials: MJ
authors.lastname: Moreno-Aliaga
authors.forename: J A
authors.initials: JA
authors.lastname: Martinez
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D054392:Adipokines / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism*; D020738:Leptin / Q000378:metabolism*; D050356:Lipid Metabolism; D008297:Male; D053858:Metabolic Networks and Pathways / Q000502:physiology; D009765:Obesity / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D054392:Adipokines; D000975:Antioxidants; D003470:Culture Media; D020738:Leptin; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D005947:Glucose; D001205:Ascorbic Acid