Search results for "Desaturase"
showing 4 items of 64 documents
Revisiting delta-6 desaturase regulation by C18 unsaturated fatty acids, depending on the nutritional status.
2009
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 t…
Mechanisms involved in lipid accumulation and apoptosis induced by 1-nitropyrene in Hepa1c1c7 cells
2011
International audience; 1-Nitropyrene (1-NP) is a nitro-polycyclic aromatic hydrocarbon (nitro-PAH) present in diesel exhaust and bound to particular matter in urban air. We show that 1-NP and the referent PAH benzo(a)pyrene (BP) induce apoptosis and a lipid accumulation dependent on cytochrome P450 1A1-metabolites in mouse hepatoma cells, whereas 1-amino-pyrene had no effect. The caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp(O-Me) fluoromethyl ketone (Z-VAD-fmk), inhibits 1-NP-induced apoptosis, but failed to alter 1-NP-triggered lipid accumulation determined by Nile red staining. We further show that cholesterol and fatty acid contents are modified after nitro-PAH exposure and that 1…
Relationship between rat liver microsomal Δ6 and Δ5 desaturase activities and fatty acid composition: comparative effects of coconut and salmon oils …
1992
International audience; The aim of this work was to compare the effects of coconut and salmon oils on rat liver microsomal Δ6 and Δ5 desaturations, during protein restriction. A higher Δ6 desaturase activity was noted in rats fed the low-protein coconut oil diet, in comparison with that occurring in rats fed either a low-protein or normal-protein salmon oil diet. No variation was observed in Δ5 desaturase activity or in 20:4n-6/ 18:2n-6 ratio. The fatty acid composition of liver microsomal phospholipids provided evidence of higher levels of 20:5n-3 and 22:6n-3 in the normal-protein salmon oil group, when compared with the low-protein salmon oil group. No influence of experimental diets on t…
Recent advances on stearoyl-Coa desaturase regulation in fatty liver diseases.
2012
Stearoyl-CoA desaturase 1 (SCD-1) is a delta-9 fatty acid desaturase that catalyzes the synthesis of monounsaturated fatty acids. Indeed, SCD-1 is the critical control point regulating hepatic lipogenesis and lipid oxidation. Due to its central role in lipid metabolism in the liver, recent studies have focused on the involvement of SCD-1 in the development of fatty liver during obesity, diabetes mellitus, hypertension, excessive alcohol consumption, and in subjects with high triglyceride blood concentrations. The accumulation of fat in liver cells can be a sign that harmful conditions are developing, possibly associated with or leading to inflammation of the liver. This review evaluates the…