Liver phospholipids of rats fed a choline‐deficient diet supplemented with choline or methionine

Beare-Rogers, Joyce L.

doi:10.1007/bf02531523

Cited by 10 publications

(3 citation statements)

References 17 publications

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“…Moreover, methionine can be made de novo from betaine or methyltetrahydrofolate (Finkelstein and Martin, 1986). Therefore, the PC/PE ratio was decreased gradually over 3 months in MCD-wild-type mice as compared with acutely (over 3 days) in CD-Pemt 2/2 mice (Beare-Rogers, 1971;Lyman et al, 1973;Yost et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

The ratio of phosphatidylcholine to phosphatidylethanolamine influences membrane integrity and steatohepatitis

et al. 2006

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Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are major phospholipids in mammalian membranes. In liver, PC is synthesized via the choline pathway or by methylation of PE via phosphatidylethanolamine N-methyltransferase (PEMT). Pemt(-/-) mice fed a choline-deficient (CD) diet develop rapid steatohepatitis leading to liver failure. Steatosis is observed in CD mice that lack both PEMT and multiple drug-resistant protein 2 (MDR2), required for PC secretion into bile. We demonstrate that liver failure in CD-Pemt(-/-) mice is due to loss of membrane integrity caused by a decreased PC/PE ratio. The CD-Mdr2(-/-)/Pemt(-/-) mice escape liver failure by maintaining a normal PC/PE ratio. Manipulation of PC/PE levels suggests that this ratio is a key regulator of cell membrane integrity and plays a role in the progression of steatosis into steatohepatitis. The results have clinical implications as patients with nonalcoholic steatohepatitis have a decreased ratio of PC to PE compared to control livers.

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Section: Discussionmentioning

confidence: 99%

The ratio of phosphatidylcholine to phosphatidylethanolamine influences membrane integrity and steatohepatitis

et al. 2006

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“…Brassica crops are important in global agriculture and oil production. High concentrations of erucic acid (C22:1) in the seed of oil-yielding Brassica species have been reported to be nutritionally undesirable ( Badawy et al 1994 , Beare-Rogers 1971 , Gopalan et al 1974 ). Therefore, a major objective for breeding is to identify and apply genetic resources to produce low erucic acid (LEA) (<2%) seeds.…”

Section: Introductionmentioning

confidence: 99%

Characterization of <i>FAE1</i> in the zero erucic acid germplasm of <i>Brassica rapa</i> L.

Yan

Cai

et al. 2015

Breed. Sci.

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The modification of erucic acid content in seeds is one of the major goals for quality breeding in oil-yielding Brassica species. However, few low erucic acid (LEA) resources are available, and novel LEA genetic resources are being sought. Fatty acid elongase 1 (FAE1) is the key gene that controls erucic acid synthesis. However, the mechanism for erucic acid synthesis in B. rapa lacks systematic study. Here, we isolated zero erucic acid lines from 1981 Chinese landraces of B. rapa and found that the formation of LEA is not attributable to variations in FAE1 coding sequences, as reported for B. napus, but may be attributable to the decrease in FAE1 expression. Moreover, the FAE1 promoter sequences of LEA and high erucic acid materials shared 95% similarity. Twenty-eight bases deletions (containing a 24-base AT-rich region) were identified approximately 1300 bp upstream from the FAE1 start codon in the LEA accessions. The genotype with the deletions co-segregated with the LEA trait in the segregating population. This study isolated an LEA B. rapa resource that can be exploited in Brassica cultivation. The promoter variations might modify the expression level of FAE1, and the results shed light on novel regulation mechanisms for erucic acid synthesis.

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“…Increased biological half-lives of the PE subfractions from choline deficient rats suggested that the conversion of PE to PC was impaired possibly because of limited availability of methionine methyl groups for methylating the PE. The possibility that methionine might play an active role in determining the liver PC composition of choline-deficient rats was indicated by Beare-Rogers (18) who recently reported that supplementary methionine was more effective than choline for increasing the liver PC arachidonic acid in rats fed a cholinedeficient diet.…”

Section: Introductionmentioning

confidence: 99%

Effect of low methionine, choline deficient diets upon major unsaturated phosphatidyl choline fractions of rat liver and plasma

Lyman

Giotas

Medwadowski

et al. 1975

Lipids

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To see how the metabolism of specific phosphatidyl choline fractions might be affected when only a limited source of methyl groups was available, rats were fed for 7 days a low methionine, choline-deficient diet or one supplemented with either choline or methionine. Prior to killing, they were injected with -14C-methyl methionine and liver and plasma phosphatidyl choline isolated and separated by argentation chromatography into 3 major unsaturated fractions. Fatty acid composition and radioactivity of the fractions were determined. Deficient rats had reduced total liver phosphatidyl choline when compared with the supplemented groups, but the proportions of 20:4 and 22:6 fatty acids in the total phosphatidyl choline were unchanged. Plasma phosphatidyl choline also was reduced sharply by the deficiency, as was its proportion of 20:4 fatty acid. Specific activities of the liver 22:6, 20:4, and 18:2 phosphatidyl choline fractions showed that deficient rats had less radioactivity in their 20:4 and 18:2 phosphatidyl choline than did the supplemented animals. Plasma phosphatidyl choline fractions presented a similar pattern. Feeding methionine or choline nearly doubled radioactive methyl group incorporation into the 20:4 phosphatidyl choline fraction of liver and plasma, while incorporation into the 22:6 phosphatidyl choline was reduced or unchanged. The results suggested that, in the rat, limited availability of methyl groups altered the metabolism of liver and plasma phosphatidyl choline fractions. Methionine, as a source of labile methyl groups, appears necessary for the normal synthesis of certain unsaturated phosphatidyl choline fractions (particularly 20:4 phosphatidyl choline). Transmethylation of phosphatidyl ethanolamine molecular species to the corresponding phosphatidyl choline species may be an important reaction in normal lipid metabolism and transport. Relative affinities for incorporation of the labeled methyl groups into the phosphatidyl choline fractions of either deficient or supplemented rats were: 22:6 less than 20:4 less than 18:2.

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Liver phospholipids of rats fed a choline‐deficient diet supplemented with choline or methionine

Cited by 10 publications

References 17 publications

The ratio of phosphatidylcholine to phosphatidylethanolamine influences membrane integrity and steatohepatitis

The ratio of phosphatidylcholine to phosphatidylethanolamine influences membrane integrity and steatohepatitis

Characterization of <i>FAE1</i> in the zero erucic acid germplasm of <i>Brassica rapa</i> L.

Effect of low methionine, choline deficient diets upon major unsaturated phosphatidyl choline fractions of rat liver and plasma

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