FGF-1 is a heparin-independent mitogen for rat hepatocytes.
We have found that in the primary culture of rat hepatocytes, the potent mitogenic activity of native FGF-1 is independent of heparin. The well-established characteristic of FGF-1 as a heparin-dependent mitogen is confirmed by human umbilical vein endothelial cells using the same preparation of FGF-1. Cross-linking experiments reveal that binding of FGF-1 to the hepatocyte cell surface receptors can be accomplished in the absence of exogenous heparin, in contrast to human endothelial cells for which it remains as a limiting factor. For both cell types, however, it is demonstrated that either endogenous or exogenous heparan sulfate/heparin moieties are essential for FGF-1 to establish receptor binding and mitogen action. Thus, the results suggest that hepatocytes harbor cell surface heparan sulfate moieties that are fully capable of utilizing FGF-1 in the environment. These results raise the possibility that FGF-1 is of differential potency for different cell types according to the nature and/or quantity of cell surface heparan sulfate moieties in vivo.
Tanahashi
T
T
Cell Biology Laboratory, National Institute of Bioscience and Human Technology, Ibaraki, Japan.
Suzuki
M
M
Mitsui
Y
Y
D000818:Animals; D001921:Brain / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects; D005260:Female; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism / Q000494:pharmacology*; D006493:Heparin / Q000494:pharmacology*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000166:cytology* / Q000187:drug effects; D008940:Mitotic Index / Q000187:drug effects; D011133:Polysaccharide-Lyases / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D014471:Umbilical Veins
D017468:Receptors, Fibroblast Growth Factor; D016220:Fibroblast Growth Factor 1; D017228:Hepatocyte Growth Factor; D006493:Heparin; D004247:DNA; D011133:Polysaccharide-Lyases; C021349:heparitinsulfate lyase