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Biochemical characteristics of isolated rat liver stellate cells

Authors

  • Masao Yamada,

    1. Departments of Medicine and Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, New York 10032
    Current affiliation:
    1. First Department of Internal Medicine, School of Medicine, Gifu University, 40 Tsukasa-machi, Gifu-City, Gifu 500, Japan
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  • William S. Blaner Ph.D.,

    Corresponding author
    1. Departments of Medicine and Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, New York 10032
    • Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 W. 168th Street, New York, New York 10032
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  • Dianne Robert Soprano,

    1. Departments of Medicine and Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, New York 10032
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  • Joseph L. Dixon,

    1. Departments of Medicine and Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, New York 10032
    Current affiliation:
    1. American Health Foundation, Valhalla, New York 10595
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  • Hild M. Kjeldbye,

    1. Departments of Medicine and Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, New York 10032
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  • Dewitt S. Goodman

    1. Departments of Medicine and Ophthalmology, Columbia University, College of Physicians and Surgeons, New York, New York 10032
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Abstract

Hepatic stellate cells play a quantitatively important role in hepatic retinoid metabolism and storage in rats maintained under normal nutritional conditions. Studies were conducted to further explore the biochemical characteristics of hepatic stellate cells. Stellate cells were isolated in high purity and yield from the livers of normal rats. The isolated cells had the morphology expected (on electron micrographs) for stellate cells, and were enriched in retinoids and in the intracellular retinoid-binding proteins. The composition of the stellate cell lipid droplets was examined. These lipid droplets were isolated in high purity and integrity from frozen and thawed stellate cell preparations by differential centrifugation. We estimate that the lipid composition of stellate cell lipid droplets consisted of approximately 42% retinyl ester, 28% triglyceride, 13% cholesterol (total) and 4% phospholipid. Thus, stellate cell lipid droplets contain substantial levels of both cholesterol and triglyceride, in addition to retinyl esters. Stellate cell homogenates were assayed for both retinol-binding protein and transthyretin by specific radioimmunoassays. Within the detection limits of these radioimmunoassays, we were unable to detect the presence of either retinol-binding protein (<9 ng per 106 cells) or transthyretin (<11 ng per 106 cells) in the stellate cell preparations. Total RNA, prepared from the isolated stellate cells, was examined by Northern blot analysis for retinol-binding protein mRNA and transthyretin mRNA, using cDNA probes for retinol-binding protein and transthyretin. Within the sensitivity of these assays, retinol-binding protein mRNA and transthyretin mRNA were not detected in stellate cells. These findings suggest that stellate cells do not synthesize or accumulate retinol-binding protein.

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