Growth effects on the insulin alteration of chang liver fatty acid metabolism

Quarfordt, Steven H.; Raymond, U; Jakoi, Lazlo; Nathans, Anne H.; Hilderman, Helen L.

doi:10.1016/0024-3205(73)90229-4

Cited by 2 publications

(4 citation statements)

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“…The relatively large size of the lipid-IT particles, however, allows ready separation from other cytosolic components by gel filtration (particularly Sepharose 2B or 4B). It is noteworthy that lipid-II, with its relatively high density and large size, is quite unusual when compared with serum lipoproteins (Sata et al, 1970;Quarfordt et al, 1972). cycloheximide-treated adrenals) Mitochondria (0.5 ml derived from 50mg of adrenal tissue) and 0.05 ml of lipid-I (derived from 5mg of adrenal tissue) were incubated for 5 min at 220C to attain a stable baseline, and pregnenolone was then added.…”

Section: Discussionmentioning

confidence: 99%

“…After discarding the lower 1 ml of the overlayed 4 or 5% sucrose solution, 'clear cytosol' fraction was obtained, and this contained both soluble cholesterol-side-chaincleavage enzyme complex and a second lipid fraction, 'lipid-II'. As described for plasma lipoproteins (Sata et al, 1970;Quarfordt et al, 1972), lipid-II was purified by chromatography on a Sephadex G-200, Sepharose 4B or Sepharose 2B column (1.6cmx 20cm) as follows: 0.1,Ci [26-14C]cholesterol (Amersham-Searle; sp. radioactivity 58Ci/ mol) was added to clear cytosol to serve as a marker for cholesterol-rich lipids or lipoproteins; 1 ml of radioactively labelled clear cytosol (containing the equivalent of 300mg of adrenal tissue) was applied to a column previously equilibrated at 80C with ST or STMK medium; elution (4ml/h) was effected with the same buffers (elution profiles were identical in both buffers), and the three peak fractions containing ["4C]cholesterol were pooled for experiments utilizing purified lipid-II fraction.…”

Section: Methodsmentioning

confidence: 99%

“…Fig. 1) on the front shoulder of the major protein peak [this corresponds to the approximate expected chromatographic migration of fl-lipoproteins, or low-density lipoproteins, in human plasma (Sata et al, 1970;Quarfordt et al, 1972)]. (0), corticotropin-plus-cycloheximide-stimulated (x) or corticotropin-stimulated adrenals (0) The mg-equiv.…”

Section: Tiesmentioning

confidence: 96%

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Non-esterified cholesterol-rich adrenal lipid fractions. Preparation, properties and preferential utilization for cholesterol side-chain cleavage by corticotropin-stimulated adrenal mitochondria

Farese¹,

Prudente²,

Chuang³

1980

Biochemical Journal

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Rat adrenal 105,000 g supernatant contains two lipid moieties, 'lipid-I' and 'lipid-II' which contain non-esterified cholesterol and stimulate cholesterol side-chain cleavage in soluble or mitochondrial enzyme systems. Lipid-I contains relatively large low-density heat-stable particles, whereas lipid-II particles are smaller, more dense and heat-labile. Lipid-I and lipid-II can be separated from clear cytosol by ultracentrifugation and gel filtration respectively. Corticotropin plus cycloheximide treatment increases the non-esterified cholesterol concentrations in the lipid fractions, and stimulatory effects of lipids on cholesterol side-chain cleavage appear to correlate with non-esterified cholesterol concentrations therein. On addition of saturating amounts of cholesterol-rich lipid, pregnenolone synthesis and cholesterol binding to cytochrome P-450 are stimulated more in mitochondria from corticotropin-stimulated adrenals than in mitochondria from control or corticotropin-plus cycloheximide-stimulated adrenals. These results support the contention that the corticotropin-induced increase in mitochondrial cholesterol side-chain cleavage involves an increase in cholesterol utilization as well as an increase in cholesterol availability.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Non-esterified cholesterol-rich adrenal lipid fractions. Preparation, properties and preferential utilization for cholesterol side-chain cleavage by corticotropin-stimulated adrenal mitochondria

Farese¹,

Prudente²,

Chuang³

1980

Biochemical Journal

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“…VLD lipoprotein, d< 1.007 g/ml; LD lipoprotein, d 1. differences in their average composition. Thus it is relevant that Eisenberg et al (1972) andQuarfordt et al (1972) found the proportion ofapolipoprotein B in human apo-VLD lipoprotein to increase markedly as the size of the parent lipoprotein molecule decreased.…”

Section: Quantitative Distribution Of An Apolipoprotein B-like Componmentioning

confidence: 99%

The distribution and partial characterization of the serum apolipoproteins in the guinea pig

Chapman

Mills

Ledford

1975

Biochemical Journal

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1. Very-low-density (VLD), low-density (LD) and high-density (HD) lipoproteins were isolated by sequential ultracentrifugation from the serum of male guinea pigs fed on a diet containing 3--4% fat. The apoproteins of these lipoproteins (apo-VLD, apo-LD and apo-HD lipoproteins) were studied after delipidation with organic solvents or extraction with tetramethylurea. 2. The major apolipoprotein of LD lipoprotein isolated by gel filtration was found to closely resemble apolipoprotein B of human serum in its chemical and physical properties. Electrophoresis in sodium dodecyl sulphate-polyacrylamide gel showed that this apoprotein consisted of a number of polypeptides. 3. Tetramethylurea precipitated an apoprotein from guinea-pig serum lipoproteins that is probably the apolipoprotein B-like component. This apoprotein accounted for about 80% of the apo-LD lipoprotein, about 55% of the apo-VLD lipoprotein and about 50% of the apo-HD lipoprotein. 4. The distribution of apolipoproteins soluble in tetramethylurea was determined by densitometric scanning of stained polyacrylamide disc gels. 5. A glycine-rich component of high electrophoretic mobility (band I) and a triplet of soluble apolipoproteins (bands II-IV) were present in both VLD and LD lipoprotein classes. These components constituted a higher proportion of the tetramethylurea-soluble apoproteins of VLD lipoprotein (60--80%) than of LD lipoprotein (40--55%). 6. Small amounts (10--15%) of a component of intermediate mobility, which contained traces of half-cystine, were also present in both VLD and LD lipoproteins. 7. A group of soluble components of basic character (bands VI-X), present as minor components of VLD lipoprotein (10--20%), constituted a major proportion (30--45%) of the soluble apoproteins of LD lipoprotein. Two of these apoproteins were rich in lysine, and two of lower electrophoretic mobility were rich in arginine. 8. The pattern of tetramethylurea-soluble apoproteins in HD lipoprotein was distinguished by the presence of two polypeptides of low electrophoretic mobility as its predominant components. One of these components, band VI, resembled the A-I apolipoprotein of man in both its amino acid profile and in its electrophoretic mobility. The second major component, band VI-B, was rich in lysine and resembled the C-I apolipoprotein of man in amino acid composition. 9. The soluble components of bands I and IX were analogous in physicochemical properties to the R-X1 and R-X2 (high-arginine polypeptide) peptides of human serum lipoproteins respectively.

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Growth effects on the insulin alteration of chang liver fatty acid metabolism

Cited by 2 publications

References 6 publications

Non-esterified cholesterol-rich adrenal lipid fractions. Preparation, properties and preferential utilization for cholesterol side-chain cleavage by corticotropin-stimulated adrenal mitochondria

Non-esterified cholesterol-rich adrenal lipid fractions. Preparation, properties and preferential utilization for cholesterol side-chain cleavage by corticotropin-stimulated adrenal mitochondria

The distribution and partial characterization of the serum apolipoproteins in the guinea pig

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