Biomaterial Database

Characterization of amylin binding sites in a human hepatoblastoma cell line. 1992

S Sheriff, and J E Fischer, and A Balasubramaniam

Department of Surgery, University of Cincinnati Medical Center, OH 45267-0558.

Amylin binding sites in a human hepatoblastoma cell line (HepG2) have been characterized in detail. 125I-Amylin (rat) bound to HepG2 cells with high affinity. Binding was reversible and selective, and dependent on time and temperature. Scatchard analysis revealed the presence of high (Kd = 0.11 +/- 0.04 nM) and low (Kd = 1.3 +/- 0.4 microM) affinity binding sites for 125I-amylin in HepG2 cells. The dissociation experiments also showed that 125I-amylin dissociated from high- and low-affinity sites. The association data, however, indicated the presence of only one binding site. Rat amylin was more potent than human amylin and rat calcitonin gene-related peptide (CGRP) in displacing 125I-amylin bound to HepG2 cells. Nonhomologous peptides did not displace 125I-amylin. Rat amylin was, however, less potent than rat CGRP in displacing 125I[Tyr0]CGRP from HepG2 cells. Pretreatment of HepG2 cells with rat amylin (10 nM) reduced the specific binding of 125I-amylin by 75%, whereas rat CGRP (10 nM) pretreatment had no effect on amylin binding. Calcitonin gene-related peptide, as well as rat and human amylin, stimulated the adenylate cyclase activity of HepG2 cell membrane preparation in a dose-dependent manner, with an order of potency of CGRP > rat amylin > human amylin. A CGRP antagonist, CGRP(8-37), significantly attenuated the stimulatory effect of both amylin and CGRP on adenylate cyclase activity. These investigations show that distinct receptors of amylin and CGRP are present in HepG2 cells, and that amylin stimulates adenylate cyclase activity through CGRP receptors. This system could now be exploited for studying amylin receptors and amylin-mediated signal transduction.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D008113	Liver Neoplasms	Tumors or cancer of the LIVER.	Cancer of Liver,Hepatic Cancer,Liver Cancer,Cancer of the Liver,Cancer, Hepatocellular,Hepatic Neoplasms,Hepatocellular Cancer,Neoplasms, Hepatic,Neoplasms, Liver,Cancer, Hepatic,Cancer, Liver,Cancers, Hepatic,Cancers, Hepatocellular,Cancers, Liver,Hepatic Cancers,Hepatic Neoplasm,Hepatocellular Cancers,Liver Cancers,Liver Neoplasm,Neoplasm, Hepatic,Neoplasm, Liver
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D005943	Gluconeogenesis	Biosynthesis of GLUCOSE from nonhexose or non-carbohydrate precursors, such as LACTATE; PYRUVATE; ALANINE; and GLYCEROL.
D006003	Glycogen
D006528	Carcinoma, Hepatocellular	A primary malignant neoplasm of epithelial liver cells. It ranges from a well-differentiated tumor with EPITHELIAL CELLS indistinguishable from normal HEPATOCYTES to a poorly differentiated neoplasm. The cells may be uniform or markedly pleomorphic, or form GIANT CELLS. Several classification schemes have been suggested.	Hepatocellular Carcinoma,Hepatoma,Liver Cancer, Adult,Liver Cell Carcinoma,Liver Cell Carcinoma, Adult,Adult Liver Cancer,Adult Liver Cancers,Cancer, Adult Liver,Cancers, Adult Liver,Carcinoma, Liver Cell,Carcinomas, Hepatocellular,Carcinomas, Liver Cell,Cell Carcinoma, Liver,Cell Carcinomas, Liver,Hepatocellular Carcinomas,Hepatomas,Liver Cancers, Adult,Liver Cell Carcinomas
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D000682	Amyloid	A fibrous protein complex that consists of proteins folded into a specific cross beta-pleated sheet structure. This fibrillar structure has been found as an alternative folding pattern for a variety of functional proteins. Deposits of amyloid in the form of AMYLOID PLAQUES are associated with a variety of degenerative diseases. The amyloid structure has also been found in a number of functional proteins that are unrelated to disease.	Amyloid Fibril,Amyloid Fibrils,Amyloid Substance,Fibril, Amyloid,Fibrils, Amyloid,Substance, Amyloid
D014407	Tumor Cells, Cultured	Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.	Cultured Tumor Cells,Neoplastic Cells, Cultured,Cultured Neoplastic Cells,Cell, Cultured Neoplastic,Cell, Cultured Tumor,Cells, Cultured Neoplastic,Cells, Cultured Tumor,Cultured Neoplastic Cell,Cultured Tumor Cell,Neoplastic Cell, Cultured,Tumor Cell, Cultured