Document Detail

Revisiting delta-6 desaturase regulation by C18 unsaturated fatty acids, depending on the nutritional status.
MedLine Citation:
PMID:  19679157     Owner:  NLM     Status:  In-Process    
Dietary polyunsaturated fatty acids (PUFA) play a key role in regulating delta-6 desaturase (D6D), the key enzyme for long-chain PUFA biosynthesis. Nevertheless, the extent of their effects on this enzyme remains controversial and difficult to assess. It has been generally admitted that C18 unsaturated fatty acids (UFAs) regulate negatively delta-6 desaturase (D6D). This inhibition has been evidenced in regard to a high glucose/fat free (HG/FF) diet used in reference. However, several nutritional investigations did not evidence any inhibition of desaturases when feeding fatty acids. Because the choice of the basal diet appeared to be of primary importance in such experiments, our goal was to reconsider the specific role of dietary UFAs on D6D regulation, depending on nutritional conditions. For that, sixteen adult Wistar rats were fed purified linoleic acid, alpha-linolenic acid or oleic acid, included in one of two diets at 4% by weight: an HG/FF or a high starch base (HS) where the pure UFAs replaced a mixed vegetable oil. Our results showed first that D6D specific activity was significantly greater when measured in presence of an HG/FF than with an HS/4% vegetable oil diet. Secondly, we found that linoleic and alpha-linolenic acids added to HG/FF reduced the specific activity of D6D. In contrast, when pure UFAs were added to an HS base, D6D specific activities remained unchanged or increased. Concordant results were obtained on D6D mRNA expression. Altogether, this study evidenced the importance of the nutritional status in D6D regulation by C18 UFAs: when used as control, HG/FF diet stimulates D6D compared with a standard control diet containing starch and 4% fats, leading to an overestimation of the D6D regulation by UFAs. Then, UFAs should be considered as repressors for unsaturated fatty acid biosynthesis only in very specific nutritional conditions.
Jérémy Skrzypski; Sandrine Bellenger; Jérôme Bellenger; Andrew Sinclair; Jean-Pierre Poisson; Christian Tessier; Mickaël Rialland; Michel Narce
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-12
Journal Detail:
Title:  Biochimie     Volume:  91     ISSN:  1638-6183     ISO Abbreviation:  Biochimie     Publication Date:    2009 Nov-Dec
Date Detail:
Created Date:  2009-11-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1264604     Medline TA:  Biochimie     Country:  France    
Other Details:
Languages:  eng     Pagination:  1443-9     Citation Subset:  IM    
INSERM UMR 866/Université de Bourgogne, Lipides Nutrition Cancer, 6 Bd Gabriel, 21000 Dijon, France.
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