title: Opposing effects of omega-3 and omega-6 long chain polyunsaturated Fatty acids on the expression of lipogenic genes in omental and retroperitoneal adipose depots in the rat.
abstract: This study aimed to determine the effect of varying dietary intake of the major n-3 PUFA in human diets, alpha-linolenic acid (ALA; 18 : 3n-3), on expression of lipogenic genes in adipose tissue. Rats were fed diets containing from 0.095%en to 6.3%en ALA and a constant n-6 PUFA level for 3 weeks. Samples from distinct adipose depots (omental and retroperitoneal) were collected and mRNA expression of the pro-lipogenic transcription factors Sterol-Retinoid-Element-Binding-Protein1c (SREBP1c) and Peroxisome Proliferator Activated Receptor-gamma (PPARgamma), lipogenic enzymes Sterol-coenzyme Desaturase1 (SCD-1), Fatty Acid Synthase (FAS), lipoprotein lipase (LPL) and glycerol-3-phosphate dehydrogenase (G3PDH) and adipokines leptin and adiponectin determined by qRT-PCR. Increasing dietary ALA content resulted in altered expression of SREBP1c, FAS and G3PDH mRNA in both adipose depots. SREBP1c mRNA expression was related directly to n-6 PUFA concentrations (omental, r(2) = .71; P < .001; Retroperitoneal, r(2) = .20; P < .002), and inversely to n-3 PUFA concentrations (omental, r(2) = .59; P < .001; Retroperitoneal, r(2) = .19; P < .005) independent of diet. The relationship between total n-6 PUFA and SREBP1c mRNA expression persisted when the effects of n-3 PUFA were controlled for. Altering red blood cell concentrations of n-3 PUFA is thus associated with altered expression of lipogenic genes in a depot-specific manner and this effect is modulated by prevailing n-6 PUFA concentrations.
authors.affiliation: FOODplus Research Centre, School of Agriculture, Food and Wine, The University of Adelaide, Adelaide 5064, Australia.
authors.forename: B S
authors.initials: BS
authors.lastname: Muhlhausler
authors.forename: R
authors.initials: R
authors.lastname: Cook-Johnson
authors.forename: M
authors.initials: M
authors.lastname: James
authors.forename: D
authors.initials: D
authors.lastname: Miljkovic
authors.forename: E
authors.initials: E
authors.lastname: Duthoit
authors.forename: R
authors.initials: R
authors.lastname: Gibson
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