title: The Hep G2 cell line in the study of growth hormone receptor/binding protein.
abstract: This study identifies specific, high affinity GH-receptors (GH-R) in human hepatoma Hep G2 cells. The binding characteristics of GH-R in the Hep G2 cells are similar to those of human liver membranes, such as the high specificity for hGH, the binding affinity (Ka = 1.7 +/- 0.5 x 10[9] M[-1]) and the molecular weight of the membrane bound GH-R (apparent 125,000 and 71,000). In addition, lower molecular weight forms (approximately 94,000 and approximately 58,000) were identified as GH-binding protein (GH-BP) in Hep G2 conditioned medium, or following incubation of Hep G2 cells, in the presence of 10 mM N-ethylmaleimide for 90 min at 30 degrees C; the latter are presumed to be shed by a proteolytic cleavage of the GH-R. Exposure of Hep G2 cells to physiologic concentrations of hGH resulted in a concentration-dependent increase in 3H-thymidine incorporation, up to 48.4 +/- 7.9% above control. In summary, the demonstration of specific, high affinity GH-R in Hep G2 cells, as well as shedding of GH-BP, suggest these cells may provide a homologous human system to study the receptor-effector interrelationship of hGH and to further our understanding of hepatocyte production of soluble GH-BP.
authors.affiliation: Department of Pharmacology, The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
authors.forename: T
authors.initials: T
authors.lastname: Amit
authors.forename: H
authors.initials: H
authors.lastname: Hacham
authors.forename: O
authors.initials: O
authors.lastname: Daily
authors.forename: P
authors.initials: P
authors.lastname: Hertz
authors.forename: R J
authors.initials: RJ
authors.lastname: Barkey
authors.forename: Z
authors.initials: Z
authors.lastname: Hochberg
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D011986:Receptors, Somatotropin / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D011986:Receptors, Somatotropin; D019382:Human Growth Hormone