uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Fatty acid desaturase indices in rats: Associations between plasma, liver and adipose tissue lipid fractions and the effects of a high-fat diet and diet-induced obesity
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Functional Pharmacology.
Department of Psychology, University of Cambridge, Cambridge.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Functional Pharmacology.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Background: Alterations in fatty acid (FA) desaturase indices are linked to obesity-related disorders. As desaturases affect FA composition increased understanding of their regulation across lipid fractions with varying functions is essential. In this study we have examined desaturases and selected FAs to establish their degree of co-regulation in five different lipid fractions and under different dietary conditions, including diet-induced obesity (DIO).

Methods: Sprague-Dawley rats were randomly grouped into three groups, one fed a chow diet ad libitum (control) and two fed a high-fat diet (HFD): one ad libitum (AL-HFD) and the other one calorically pair fed to the chow-fed group (HFD-paired). FA composition in subcutaneous adipose tissue triacylglycerols (SAT-TG), liver (phospholipids and triacylglycerols) and plasma (phospholipids and cholesterol esters) was assessed. Delta-5 desaturase (D5D), delta-6 desaturase (D6D) and stearoyl-CoA-desaturase 1 (SCD-16) indices were calculated from product-to-precursor FA ratios and proportions of long-chain FAs were measured.

Results: Positive correlations were found for the desaturase indices between the five lipid fractions, especially for SCD-16 and almost exclusively between liver and plasma fractions. Only SCD-16 in SAT-TG of the AL-HFD group correlated with gain in body weight. Independent of weight gain, the HFD decreased all SCD-16 indices and most FA proportions, but D5D and D6D indices were fraction- and tissue-dependently increased.

Conclusion: Desaturase indices are especially correlated for SCD-16 and between lipid and plasma lipid fractions, suggesting that SAT-TG desaturation is differentially regulated compared with the other studied lipid fractions. The correlations are however influenced by diet and weight gain, further suggesting such factors should be taken into account when using desaturase indices.

Keyword [en]
diet-induced obesity, delta-5, delta-6, scd-1, fatty acid composition, high-fat diet, subcutaneous adipose tissue, scd-16
National Category
Nutrition and Dietetics
Research subject
Nutrition; Nutrition
URN: urn:nbn:se:uu:diva-196190OAI: oai:DiVA.org:uu-196190DiVA: diva2:609429
Available from: 2013-03-05 Created: 2013-03-05 Last updated: 2013-04-02
In thesis
1. Intestinal Gene Expression Profiling and Fatty Acid Responses to a High-fat Diet
Open this publication in new window or tab >>Intestinal Gene Expression Profiling and Fatty Acid Responses to a High-fat Diet
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The gastrointestinal tract (GIT) regulates nutrient uptake, secretes hormones and has a crucial gut flora and enteric nervous system. Of relevance for these functions are the G protein-coupled receptors (GPCRs) and the solute carriers (SLCs). The Adhesion GPCR subfamily is known to mediate neural development and immune system functioning, whereas SLCs transport e.g. amino acids, fatty acids (FAs) and drugs over membranes. We aimed to comprehensively characterize Adhesion GPCR and SLC gene expression along the rat GIT. Using qPCR we measured expression of 78 SLCs as well as all 30 Adhesion GPCRs in a twelve-segment GIT model. 21 of the Adhesion GPCRs had a widespread (≥5 segments) or ubiquitous (≥11 segments) expression. Restricted expression patterns were characteristic for most group VII members. Of the SLCs, we found the majority (56 %) of these transcripts to be expressed in all GIT segments. SLCs were predominantly found in the absorption-responsible gut regions. Both Adhesion GPCRs and SLCs were widely expressed in the rat GIT, suggesting important roles. The distribution of Adhesion GPCRs defines them as a potential pharmacological target.

FAs constitute an important energy source and have been implicated in the worldwide obesity increase. FAs and their ratios – indices for activities of e.g. the desaturase enzymes SCD-1 (SCD-16, 16:1n-7/16:0), D6D (18:3n-6/18:2n-6) and D5D (20:4n-6/20:3n-6) – have been associated with e.g. overall mortality and BMI. We examined whether differences in FAs and their indices in five lipid fractions contributed to obesity susceptibility in rats fed a high fat diet (HFD), and the associations of desaturase indices between lipid fractions in animals on different diets. We found that on a HFD, obesity-prone (OP) rats had a higher SCD-16 index and a lower linoleic acid (LA) proportions in subcutaneous adipose tissue (SAT) than obesity-resistant rats. Desaturase indices were significantly correlated between many of the lipid fractions. The higher SCD-16 may indicate higher SCD-1 activity in SAT in OP rats, and combined with lower LA proportions may provide novel insights into HFD-induced obesity. The associations between desaturase indices show that plasma measurements can serve as proxies for some lipid fractions, but the correlations seem to be affected by diet and weight gain.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 98 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 872
Adhesion GPCR, delta-5 desaturase, delta-6 desaturase, desaturase index, Diet-induced obesity, estimated desaturase activity, fatty acid composition, gas chromatography, gastrointestinal tract, G-protein coupled receptor, high-fat diet, intestine, linoleic acid, liver, mRNA expression, palmitoleic acid, plasma, phospholipids, proximodistal, RT-qPCR, solute carrier, SCD-1, SCD-16, SCD-18, stearoyl-CoA desaturase, subcutaneous adipose tissue, subsection, triacylglycerols.
National Category
Nutrition and Dietetics Cell and Molecular Biology Medical Genetics
Research subject
Medical Genetics; Nutrition; Nutrition
urn:nbn:se:uu:diva-196207 (URN)978-91-554-8612-9 (ISBN)
Public defence
2013-04-18, B22, Biomedicinskt centrum, Husargatan 3, UPPSALA, 13:15 (English)
Available from: 2013-03-27 Created: 2013-03-05 Last updated: 2013-04-02Bibliographically approved

Open Access in DiVA

No full text

By organisation
Functional PharmacologyDepartment of Public Health and Caring Sciences
Nutrition and Dietetics

Search outside of DiVA

GoogleGoogle Scholar

Total: 260 hits
ReferencesLink to record
Permanent link

Direct link