An in vivo evaluation in man of the transfer of esterified cholesterol between lipoproteins and into the liver and bile

Schwartz, Charles C.; Vlahčevič, Z. Reno; Halloran, L G; Swell, Leon

doi:10.1016/0005-2760(81)90201-0

Cited by 66 publications

(25 citation statements)

References 17 publications

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“…These precursor pools are known to contain '500 ,um FC (minimum estimate), receive NSC directly, exchange preferentially with HDL-FC, and have turnover times of 1-1.5 h (4-7). All of these kinetic features are compatible with those of C (12). The studies of Gould et al (26), using…”

Section: Discussionsupporting

confidence: 74%

“…The extent of variation in the size of C(12), the rapidly exchanging tissue pool, was small and ranged from 4,491 to 6,901 umol. In most subjects the size of C (12) was approximately twice the size of the total plasma FC pool. Confidence was gained in the model structure by the finding of similar values between subjects for most of the adjustable rate constants and masses.…”

Section: Resultsmentioning

confidence: 97%

“…The specific activity fits and parameter values were not sensitive to this assumption. For example, a twofold change in U1 only affected the parameters L(4, 12) and L (12,4), and the maximum change was <10%. The compartment from which cholesterol is lost from the body (bile acid and biliary cholesterol precursor pools) could not be identified precisely from the present experimental data.…”

Section: Resultsmentioning

confidence: 98%

“…1, bottom, and 3) could not be attributed solely to transfer of FC from the a-to the ,B-fraction. To simulate this steep decline it was necessary to incorporate a pathway from HDL-FC to a nonplasma compartment, designated as G (12). Second, the major pathway of FC transport from nonplasma to plasma compartments was found to be into HDL.…”

Section: Resultsmentioning

confidence: 99%

“…Five (12). Briefly, the filter paper strips were removed and the P-lipoproteins were precipitated from the plasma with heparin MnCl2 (13 (15), the lower chloroform phase was collected and subjected to silicic acid column chromatography (11) to separate the free cholesterol from esterified cholesterol.…”

mentioning

confidence: 99%

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Central Role of High Density Lipoprotein in Plasma Free Cholesterol Metabolism

Schwartz¹,

Vlahčevič²,

Berman³

et al. 1982

J. Clin. Invest.

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A B S T R A C T This study was designed to provide direct information on the in vivo metabolism in man of free (unesterified) the a-and fB-lipoproteins increased for 3 h. During this period the a-free cholesterol specific activity was higher than the ,B specific activity. After administration of VLDL and LDL labeled with free cholesterol, the a-free cholesterol specific activity reached a peak value within 20 min, at which time it was considerably lower than the 13-free cholesterol specific activity. When HDL labeled with free cholesterol was administered, a precursor product relationship was observed between the a-free cholesterol (precursor) and ,3-free cholesterol (product) specific activities.A multicompartmental model was developed that contained the simplest structure necessary to fit all of the data obtained. The kinetic analysis revealed the presence of extensive exchange (20-85 ,umol/min) of free cholesterol between HDL and a tissue pool(s) enriched with newly synthesized free cholesterol. It was found that virtually all (>95%) of the free cholesterol

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Section: Discussionsupporting

confidence: 74%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Central Role of High Density Lipoprotein in Plasma Free Cholesterol Metabolism

Schwartz¹,

Vlahčevič²,

Berman³

et al. 1982

J. Clin. Invest.

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Proposed mechanisms of cholesterol‐lowering action of plant sterols

Trautwein

Duchateau

Lin

et al. 2003

Euro J Lipid Sci & Tech

203

132

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The aim of this review is to summarise the current understanding concerning the mechanism of action by which plant sterols affect cholesterol metabolism and thus exert their cholesterol-lowering effect. The review will focus on the gut, e.g. on the physico-chemical effects at the gastric-duodenal level, on absorptive site effects, and on intra-cellular trafficking, i.e. effects at the epithelial cell level.

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Bile acid metabolism in human hyperthyroidism

1989

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Decreased levels of serum cholesterol are a well-recognized finding in hyperthyroidism. Since the conversion to bile acids is an important pathway for the elimination of cholesterol, we studied primary bile acid kinetics in seven hyperthyroid patients before and after medical treatment. Pool sizes, fractional turnover and synthesis rates of cholic acid and chenodeoxycholic acid were determined after oral administration of 50 mg [13C]cholic acid and 50 mg [13C]chenodeoxycholic acid. 13C/12C isotope ratios in serum were measured by capillary gas chromatography/electron impact mass spectrometry. Compared with the euthyroid state, serum cholesterol levels were distinctly lower in hyperthyroidism (150 +/- 33 vs. 261 +/- 51 mg per dl, p less than 0.01). Thyroid hormone excess caused a 34% reduction in cholic acid synthesis (5.8 +/- 2.8 vs. 7.9 +/- 4.2 mu moles per kg per day, p less than 0.02), which was associated with a 47% decrease in cholic acid pool size (11.7 +/- 3.4 vs. 22.0 +/- 5.2 mu moles per kg, p less than 0.01). Chenodeoxycholic acid kinetics exhibited no apparent changes. Thus, total primary bile acid synthesis was diminished by 20% in hyperthyroidism. After normalization of thyroid function, the ratio of cholic acid/chenodeoxycholic acid pool size increased in all patients. This was paralleled by a rise in the ratio of concentrations of cholic acid/chenodeoxycholic acid in serum. The depression of cholic acid synthesis in the presence of unaltered subjects is compatible with an inhibition of hepatic 12 alpha-hydroxylation by thyroid hormone. Furthermore, evidence is provided that, in man, the low serum cholesterol levels found during hyperthyroidism are not caused by an increased conversion of cholesterol to bile acid.

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An in vivo evaluation in man of the transfer of esterified cholesterol between lipoproteins and into the liver and bile

Cited by 66 publications

References 17 publications

Central Role of High Density Lipoprotein in Plasma Free Cholesterol Metabolism

Central Role of High Density Lipoprotein in Plasma Free Cholesterol Metabolism

Proposed mechanisms of cholesterol‐lowering action of plant sterols

Bile acid metabolism in human hyperthyroidism

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