Liver contains heparin-binding growth factors as the major growth factor for cultured fibroblasts

Authors

  • Takayuki Nagasaki,

    1. Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267–0524
    Current affiliation:
    1. Department of Anatomy and Cell Biology, Columbia University, College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032
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  • Dr. Michael A. Lieberman

    Corresponding author
    1. Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267–0524
    • Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, 231 Bethesda Avenue, Cincinnati, OH 45267–0524
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Abstract

The presence of heparin-binding growth factors in liver was investigated by measuring the DNA synthesis stimulatory activity of liver extracts using quiescent fibroblasts as target cells. It was found that cytosolic fractions of mouse, rat and human liver, as well as isolated rat hepatocytes, contain a large amount of growth stimulatory activity. Most liver cytosolic activity is due to heparin-binding growth factors, because > 90% of the activity bound to a heparin affinity column in the presence of 0.8 mol/L NaCl, and was quantitatively eluted with 2 mol/L NaCl. Purification of these factors from both mouse and rat liver indicated the presence of both heparin-binding growth factor-1 and 2 in liver extracts. The level of the heparin-binding growth factors, as estimated from the biological activity, is approximately 1 μg/gm mouse liver and 0.1 μg/gm rat and human liver. Heparin-binding growth factor-1–like factors were 10 times as abundant as heparin-binding growth factor-2–like factors. These data indicate that the cytosolic fractions of mouse, rat and human liver contain heparin-binding growth factors as the primary growth factor for fibroblasts, and heparin binding growth factor-1–like molecules account for most of the cytosolic activity in both mouse and rat liver. (HEPATOLOGY 1991;13:6–14).

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