Intracellular distribution of endothelin-1 receptors in rat liver cells.
We studied the binding of (125I)-endothelin-1 as well as that of the vasopressin analogue (125I)-[8-phenylpropionyl]-LVP to purified plasma membranes, Golgi cisternae and cell nuclei from rat liver. Cell organelles were isolated by differential centrifugation and discontinuous sucrose gradients. Endothelin-1 exhibited specific binding to plasma membranes, Golgi cisternae and nuclei, while the binding of (125I)-[8-phenylpropionyl]-LVP was restricted to the plasma membranes. The number of receptors (Bmax) and the binding constants (Kd) were determined by Scatchard analysis of competition binding studies. In all cases only one class of Et-1 binding sites could be detected. The presence of Et-1 receptors on the Golgi complex either indicates that the receptor is glycosylated within the cisternae or alternatively, there exists a recycling pathway. The unexpected finding of Et-1 receptors on highly purified nuclei suggests that this peptide may exert part of its biological functions intracellularly via the nucleus.
Hocher
B
B
Abteilung für Innere Medizin, Klinikum Steglitz, Freie Universität Berlin, Germany.
Rubens
C
C
Hensen
J
J
Gross
P
P
Bauer
C
C
D000818:Animals; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D016232:Endothelins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008236:Lypressin / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017466:Receptors, Endothelin
D016232:Endothelins; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; C074113:vasopressin, 8-Lys-8-phenylpropionyl-; D008236:Lypressin