Lipid metabolism in the perfused chicken liver. The uptake and metabolism of oleic acid, elaidic acid, <i>cis</i>-vaccenic acid, <i>trans</i>-vaccenic acid and stearic acid

Bickerstaffe, R.; Annison, E. F.

doi:10.1042/bj1180433

Cited by 36 publications

(22 citation statements)

References 26 publications

(17 reference statements)

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“…Furthermore, 35 years ago, Bickerstaffe and Annison (1970) observed negative effects of oleic, linoleic, and linolenic acids on goat mammary SCD activity measured in vitro, which have been partly confirmed by our in vivo studies on goats (see earlier section). The addition of trans-11 C18:1 increased SCD mRNA abundance in bovine MEC (Matitashvili & Bauman, 2000) and SCD activity in the bovine MAC-T cell line (Jayan & Herbein, 2000).…”

Section: In Vitro Studies On the Effect Of Fatty Acids On Lipogenesissupporting

confidence: 80%

Expression and Nutritional Regulation of Lipogenic Genes in the Ruminant Lactating Mammary Gland

Bernard

Leroux

Chilliard

Advances in Experimental Medicine and Biology

206

225

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The effect of nutrition on milk fat yield and composition has largely been investigated in cows and goats, with some differences for fatty acid (FA) composition responses and marked species differences in milk fat yield response. Recently, the characterization of lipogenic genes in ruminant species allowed in vivo studies focused on the effect of nutrition on mammary expression of these genes, in cows (mainly fed milk fat-depressing diets) and goats (fed lipid-supplemented diets). These few studies demonstrated some similarities in the regulation of gene expression between the two species, although the responses were not always in agreement with milk FA secretion responses. A central role for trans-10 C18:1 and trans-10, cis-12 CLA as regulators of milk fat synthesis has been proposed. However, trans-10 C18:1 does not directly control milk fat synthesis in cows, despite the fact that it largely responds to dietary factors, with its concentration being negatively correlated with milk fat yield response in cows and, to a lesser extent, in goats. Milk trans-10, cis-12 CLA is often correlated with milk fat depression in cows but not in goats and, when postruminally infused, acts as an inhibitor of the expression of key lipogenic genes in cows. Recent evidence has also proven the inhibitory effect of the trans-9, cis-11 CLA isomer. The molecular mechanisms by which nutrients regulate lipogenic gene expression have yet to be well identified, but a central role for SREBP-1 has been outlined as mediator of FA effects, whereas the roles of PPARs and STAT5 need to be determined. It is expected that the development of in vitro functional systems for lipid synthesis and secretion will allow future progress toward (1) the identification of the inhibitors and activators of fat synthesis, (2) the knowledge of cellular mechanisms, and (3) the understanding of differences between ruminant species.

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Section: In Vitro Studies On the Effect Of Fatty Acids On Lipogenesissupporting

confidence: 80%

Expression and Nutritional Regulation of Lipogenic Genes in the Ruminant Lactating Mammary Gland

Bernard

Leroux

Chilliard

Advances in Experimental Medicine and Biology

206

225

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“…In this goal, rats were used in the fed state because this nutritional condition was shown to depress FA oxidation in liver and most other organs [35], which made all unbound FA available for TAG and PL synthesis. This ex vivo study shows that trans-11 and trans-9 were not interchangeable substrates for the esterification reactions in intact or disrupted liver cells, as well and trans-9 a common linear aspect as for saturated FA [36][37][38]. Enzyme activities mainly depend on specific protein synthesis regulated by genes and on affinity of enzymes for their substrates.…”

Section: Discussionmentioning

confidence: 93%

“…In perfused liver, trans-9 and trans-11, as well as stearic acid (C 18:0 ), were principally recovered on the 1-and 3-positions of TAG, while cis-9 and -11 isomers were mainly present on the 2-position [36]. With this specific information, our results show that, in intact and disrupted cells, the affinities of either trans-C 18:1 for the external 2 positions of TAG were equivalent and always at a significantly less extent than those of either cis-C 18:1 for the internal position alone.…”

Section: Esterification Of Isomers Into Tag and Pl Of Liver Cellsmentioning

confidence: 98%

Vaccenic and Elaidic Acid Equally Esterify into Triacylglycerols, but Differently into Phospholipids of Fed Rat Liver Cells

Degrace

Gresti

et al. 2011

Lipids

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Elaidic acid (trans-9-C₁₈:₁ or trans-9) is assumed to exert atherogenic effects due to its double bond configuration. The possibility that trans-9 and vaccenic acid (trans-11-C₁₈:₁ or trans-11), its positional isomer, were biochemically equivalent and interchangeable compounds, was investigated by reference to their cis-isomers through esterification-related activities using rat liver cells and subcellular fractions. In hepatocytes, both trans-C₁₈:₁ were incorporated to the same extent in triacylglycerols, but trans-9 was more esterified than trans-11 into phospholipids (P < 0.05). Glycerol-3-phosphate acyltransferase activity in microsomes was lower with trans-11 than with trans-9, while this activity in mitochondria was ~40% greater with trans-11 than with trans-9 (P < 0.05). Activity of 2-lysophosphatidic acid acyltransferase in microsomes was of comparable extent with both trans isomers, but activity of 2-lysophosphatidylcholine acyltransferase was significantly greater with trans-9 than with trans-11 at P < 0.01. Lipoproteins secreted by hepatocytes reached equivalent levels in the presence of any isomers, but triacylglycerol production was more elevated with trans-11 than with trans-9 at P < 0.05. Cholesterol efflux from previously labelled hepatocytes was lower with trans-11 than with trans-9. When these cells were exposed to either trans-C₁₈:₁, the gene expression of proteins involved in fatty acid esterification and lipoprotein synthesis was unaffected, which indicates that the biochemical differences essentially depended on enzyme/substrate affinities. On the whole, vaccenic and elaidic acid were shown to incorporate cell phospholipids unequally, at least in vitro, which suggests they can differently affect lipid metabolic pathways in normal cells.

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“…Such a difference could result from a particular conformation of the double bonds of rumenic acid (cis, trans conjugated double bond) compared to the cis conformation of the oleic acid double bond. Indeed, Bickerstaffe and Annison [35] previously showed, in the perfused chicken liver, that the incorporation of mono-unsaturated fatty acid by hepatic cells depended more on the spatial conformation of the double bonds rather than on the position along the hydrocarbon chain, the trans-monounsaturated FA being more easily incorporated than the cis-monounsaturated FA (i.e., oleic acid). Although rumenic acid was better utilized by hepatic cells than oleic acid in our experimental conditions, the efficiency of hepatic uptake of both FA by bovine hepatocytes was lower than that observed in the rat liver [21].…”

Section: Discussionmentioning

confidence: 99%

In vitro metabolism of rumenic acid in bovine liver slices

et al. 2005

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-Ruminant products are the major source of CLA for humans. However, during periods of fat mobilization, the liver might play an important role in CLA metabolism which would limit the availability of the latter for muscles and milk. In this context, rumenic acid (cis-9, trans-11 CLA) metabolism in the bovine liver (n = 5) was compared to that of oleic acid (n = 3) by using the in vitro liver slice method. Liver slices were incubated for 17 h in a medium containing 0.75 mM of FA mixture and 55 µM of either [1-14 C] rumenic acid or [1-14 C] oleic acid at 37 °C under an atmosphere of 95% O 2 -5% CO 2 . Rumenic acid uptake by liver slices was twice (P = 0.009) that of oleic acid. Hepatic oxidation of both FA (> 50% of incorporated FA) led essentially to the production of acidsoluble products and to a lower extent to CO 2 production. Rumenic acid was partly converted (> 12% of incorporated rumenic acid) into conjugated C18:3. CLA and its conjugated derivatives were mainly esterified into polar lipids (71.7%), whereas oleic acid was preferentially esterified into neutral lipids (59.8%). Rumenic acid secretion as part of VLDL particles was very low and was onefourth lower than that of oleic acid. In conclusion, rumenic acid was highly metabolized by bovine hepatocytes, especially by the oxidation pathway and by its conversion into conjugated C18:3 for which the biological properties need to be elucidated. rumenic acid / oleic acid / metabolism / liver / bovine Abbreviations: ASP, acid-soluble products; BSA, bovine serum albumin; CLA, conjugated linoleic acid; FA, fatty acids; NL, neutral lipids; PL, polar lipids; VLDL, very-low density lipoproteins.

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Lipid metabolism in the perfused chicken liver. The uptake and metabolism of oleic acid, elaidic acid, cis-vaccenic acid, trans-vaccenic acid and stearic acid

Cited by 36 publications

References 26 publications

Expression and Nutritional Regulation of Lipogenic Genes in the Ruminant Lactating Mammary Gland

Expression and Nutritional Regulation of Lipogenic Genes in the Ruminant Lactating Mammary Gland

Vaccenic and Elaidic Acid Equally Esterify into Triacylglycerols, but Differently into Phospholipids of Fed Rat Liver Cells

In vitro metabolism of rumenic acid in bovine liver slices

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