Effects of Feeding High-Fat Diets to Rats: Metabolism of Erucic Acid (C 22:1 n-9) in the Perfused Liver and Secretion of Metabolites to the Perfusate

Rønneberg, Ragnhild; Hølmer, Gunhild; Lambertsen, Georg

doi:10.1159/000177214

Cited by 5 publications

(5 citation statements)

References 7 publications

(7 reference statements)

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“…In this con nection it is an interesting observation that the induced oxidative capacity was similar in both groups, irrespective of the dietary fat. Hence, these results are in accordance with our previous findings on the distribu tion and chain shortening of 22:1 in perfused rat livers [9].…”

Section: Discussionsupporting

confidence: 94%

“…Perfusion experiments with 14-14C erucic acid have shown a relatively low secretion of labelled TG from the rat liver [6,9]. How ever, in the present paper, and in accordance with other reports [27,28,34] appreciable amounts of labelled TG (40-50% of the total radioactivity in the medium) were secreted from the hepatocytes, presumably as VLDL-TG.…”

Section: Discussionsupporting

confidence: 92%

“…Divergent results have lately been reported regarding these factors. We have found PO to be a conve nient comparable fat to PHMO, due to its high content of 18:1, and adequate amounts of linoleic acid [9,10,19]. The present ex periment with hepatocytes has, compared to in vivo or perfusion studies, the advantages of a simplified system and the possibilities of studying different treatments (e.g.…”

Section: Discussionmentioning

confidence: 80%

“…In our experiment, the chain shortening of 22:1 was not stimulated more in the group fed PHMO than in the PO group, even though no extra carnitine was added to the incubation medium, suggesting a relative low importance of the peroxisomal activity when the esterifi cation as well as the mitochondrial pathways are functionating in the well-nourished cells. We have previously observed that a chain shortening of 22:1 may take place in the mito chondria as well as in the peroxisomes [9] when the rats are fed a diet adequate in linoleic acid. Chain-shortened monoenoic fatty acids were found in the phospholipids, espe cially when incubating with 22:1, whereas the labelling in free fatty acids and TG fractions was detected mainly in the original fatty acids, 14C-18:1 and l4C-22:l.…”

Section: Discussionmentioning

confidence: 98%

“…In a liver perfusion study [9] we demon strated a possible chain shortening of 22:1 to 20:1 and 18:1 in the mitochondria as well as in the peroxisomes, a direct incorporation of erucic acid in the TG and also the secretion of free fatty acids. Christiansen et al [7] fed PHMO and peanut oil to rats for 3 weeks and found by incubation a delayed uptake of 22:1 in the hepatocytes compared to 16:0, but an increased oxidation of 22:1 in the PHMO group, relative to the peanut oil group.…”

Section: Introductionmentioning

confidence: 96%

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Comparative Metabolism of Erucic and Oleic Acid in Hepatocytes from Rats Fed Partially Hydrogenated Marine Oil or Palm Oil

1987

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Rats were fed for 8 weeks high fat diets containing 20% of either palm oil (PO) or linoleic-supplemented partially hydrogenated marine oil (PHMO). Hepatocytes were isolated from rats fasted overnight. Incubations were performed with albumin bound [10–¹⁴C] oleic acid and [14–¹⁴C] erucic acid, respectively, for 15 or 60 min. The cell viability was better than 90% after 60 min of incubation. The incorporation of radioactive metabolites into lipids of the cells and of the secreted products was determined. The uptake and channelling of 18:1 and 22:1 into various lipid classes in the hepatocytes were different, but were little influenced by the diets. Erucic acid disappeared more rapidly from the incubation medium than 18:1 at both incubation times and for both dietary groups, and was mainly incorporated into the hepatocyte triglycerides and found in the free fatty acid pool, whereas only small amounts of labelling were detected in the phospholipids. Oleic acid, however, was readily incorporated into both phospholipids and triglycerides, and little was found in the free fatty acid pool. For both the triglycerides and the free fatty acids more than 90% of the radioactivity was represented by the incubation fatty acid. Chain-shortened products were found in the phospholipids, especially after incubation with 22:1. The chain-shortening capacity was somewhat higher in the PHMO group, relative to the PO group. At both incubation times, the major part (80–90%) of the total radioactivity was found in the lipid-soluble fraction of the incubation medium, and for both groups 60–80% still as the original incubation fatty acid. 20–30% of the radioactivity was found in the triglycerides secreted from the cells. Phospholipids were secreted in minor amounts (1–5%). Water soluble products constituted 3–7% at 15 min of incubation, increasing to 10–12% at 60 min, highest when incubating with 22:1 and similar for both dietary groups.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 96%

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Comparative Metabolism of Erucic and Oleic Acid in Hepatocytes from Rats Fed Partially Hydrogenated Marine Oil or Palm Oil

1987

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Is dietary erucic acid hepatotoxic in pregnancy? an experimental study in rats and hamsters

Reyes

Ribalta

Hernández³

et al. 1995

Hepatology

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The hypothesis that dietary erucic acid may contribute to the pathogenesis of intrahepatic cholestasis of pregnancy has been examined in pregnant rats and hamsters after prolonged feeding of diets containing 25% rapeseed oil rich in erucic acid (40% of fatty acids) or corn oil, without erucic acid. Both dietary oils were well tolerated, although weight gain was 17% to 20% less in animals receiving rapeseed oil. Rats and hamsters were studied on the last day of pregnancy and compared with age- and diet-matched nonpregnant animals. Histological examination showed no major morphologic abnormalities in liver, heart, kidneys, and adrenals. Similar microscopic deposits of fat were found in the livers and hearts of pregnant hamsters of both dietary groups. Chromatographic analysis of fatty acids in liver, heart, and kidney homogenates of hamsters and in isolated rat liver cells reflected the fatty acid composition of the dietary oils: oleic (18:1) and linoleic (18:2) acids were among the predominant fatty acids. Erucic acid was found in a higher proportion in the heart (14% by weight of total fatty acids) than in the liver (3%) and kidneys (3%) of animals fed rapeseed oil. Bile flow and biliary lipid composition was similar in rats and hamsters fed rapeseed or corn oil. Bile flow tended to be less in pregnant than in nonpregnant animals. Pregnant hamsters fed rapeseed oil tended to have the lowest bile flow. The lithogenic index of bile was slightly decreased in pregnant rats and increased in pregnant hamsters, although these proportional changes were similar for both diets. In all circumstances the lithogenic index remained below a value of 1.(ABSTRACT TRUNCATED AT 250 WORDS)

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Erucic Acid is Differentially Taken up and Metabolized in Rat Liver and Heart

Murphy

Golovko

2008

Lipids

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Because X-linked adrenoleukodystrophy is treated using erucic acid (22:1n-9), we assessed its metabolism in rat liver and heart following infusion of [14-(14)C]22:1n-9 (170 Ci/kg) under steady-state-like conditions. In liver, 2.3-fold more tracer was taken up as compared to heart, accounted entirely by increased incorporation into the organic fraction (4.2-fold). The amount of tracer entering the aqueous fraction, which represents beta-oxidation, was not different between groups; however a significantly elevated proportion of tracer was in the heart aqueous fraction. In both tissues, 76% of the radioactivity found in the organic fraction was esterified in neutral lipids, while only about 10% was found esterified into phospholipids. In liver, 56% of lipid radioactivity was found in cholesteryl esters, whereas in heart 64% was found in triacylglycerols. Because 22:1n-9 can be chain shortened, we assessed tracer metabolism using phenacyl fatty acid derivatives esterified from saponified esterified neutral lipid (triacylglycerol/cholesteryl ester) and phospholipid fractions. In heart esterified neutral lipids, 75% of tracer was recovered as 22:1n-9 and only 10% as oleic acid (18:1n-9), while in liver only 25% of the tracer was recovered as 22:1n-9, while 50% was found as stearic acid (18:0) and 10% as 18:1n-9. In liver and heart phospholipids, the tracer was distributed amongst the n-9 fatty acid family. Thus, 22:1n-9 under went tissue selective metabolism, with conversion to 18:0 the dominant pathway in the liver presumably for export in the neutral lipids, while in heart it was found primarily as 22:1n-9 in neutral lipids and used for beta-oxidation.

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Effects of Feeding High-Fat Diets to Rats: Metabolism of Erucic Acid (C 22:1 n-9) in the Perfused Liver and Secretion of Metabolites to the Perfusate

Cited by 5 publications

References 7 publications

Comparative Metabolism of Erucic and Oleic Acid in Hepatocytes from Rats Fed Partially Hydrogenated Marine Oil or Palm Oil

Comparative Metabolism of Erucic and Oleic Acid in Hepatocytes from Rats Fed Partially Hydrogenated Marine Oil or Palm Oil

Is dietary erucic acid hepatotoxic in pregnancy? an experimental study in rats and hamsters

Erucic Acid is Differentially Taken up and Metabolized in Rat Liver and Heart

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