title: Basic fibroblast growth factor-induced increase in 125I-human chorionic gonadotropin binding to luteinizing hormone receptors in cultured immature Leydig cells is mediated by binding to heparan sulfate proteoglycans.
abstract: Previous studies have shown that basic fibroblast growth (bFGF) has a biphasic effect on 125I-hCG binding to LH receptors in cultured Leydig cells from immature rats. Low concentrations of bFGF (0.1-1.0 ng/ml) progressively decreased binding, while higher concentrations (10-100 ng/ml) progressively increased binding above nadir levels. In the present studies, treatment of cultured immature Leydig cells with heparinase I and/or heparinase III, which enzymatically remove heparan sulfate proteoglycans, had no effect on basal binding of 125I-hCG to LH receptors or the decrease in binding due to treatment with low bFGF concentrations; however, this treatment dramatically reduced the secondary increase in binding following the addition of higher bFGF concentrations. These results strongly support the idea that the secondary increase in 125I-hCG binding to LH receptors elicited by treatment with higher bFGF concentrations is mediated by bFGF binding to heparan sulfate proteoglycans associated with the plasma membrane and/or extracellular matrix.
authors.affiliation: Research Service, Dorn Veterans' Hospital, Columbia, SC.
authors.forename: E P
authors.initials: EP
authors.lastname: Murono
authors.forename: A L
authors.initials: AL
authors.lastname: Washburn
authors.forename: D P
authors.initials: DP
authors.lastname: Goforth
authors.forename: N
authors.initials: N
authors.lastname: Wu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002808:Chondroitin Lyases / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D019812:Heparan Sulfate Proteoglycans; D019763:Heparin Lyase; D006497:Heparan Sulfate / Q000378:metabolism*; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology; D007985:Leydig Cells / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010727:Phosphoric Diester Hydrolases / Q000494:pharmacology; D011133:Polysaccharide-Lyases / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D011509:Proteoglycans / Q000378:metabolism*; D051381:Rats; D011974:Receptors, LH / Q000378:metabolism*; D013268:Stimulation, Chemical
chemical_list: D002808:Chondroitin Lyases; D006063:Chorionic Gonadotropin; D016222:Fibroblast Growth Factor 2; D019812:Heparan Sulfate Proteoglycans; D019763:Heparin Lyase; D006497:Heparan Sulfate; D006821:Hyaluronoglucosaminidase; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010727:Phosphoric Diester Hydrolases; D011133:Polysaccharide-Lyases; D011509:Proteoglycans; D011974:Receptors, LH