These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Correlation between guanine nucleotide effect and reversible binding property of endothelin analogs.
    Author: Nambi P, Pullen M, Aiyar N.
    Journal: Neuropeptides; 1996 Feb; 30(1):109-14. PubMed ID: 8868308.
    Abstract:
    [125I]-IRL-1620 and [125I]-ET-1 (readily reversible and essentially irreversible endothelin (ET) receptor agonists, respectively) were used to demonstrate the relationship between the reversible binding nature of ET receptor agonists and guanine nucleotide effect using ETB receptors as the model system. Addition of increasing concentrations of GTP gamma s to membranes prepared from Chinese hamster ovary (CHO) cells stably transfected with human ETB receptors, dog lung and pig lung decreased [125I]-IRL-1620 binding to these membranes between 50% and 60%, whereas [125I]-ET-1 binding to these receptors was unaffected by GTP gamma s. Saturation binding experiments in the absence and presence of 100 microM GTP gamma s indicated that the apparent dissociation constant [Kd(apparent)] for [125I]-IRL-1620 was increased 2 to 2.4-fold in all 3 membrane preparations in the presence of GTP gamma s compared to its absence. There was no difference in the apparent dissociation constants of [125I]-ET-1 in the presence and absence of GTP gamma s in these membrane preparations. This inhibitory effect was specific for guanosine triphosphate since adenine nucleotides failed to decrease the affinity of [125I]-IRL-1620 for the receptors. The correlation between guanine nucleotide effect and reversible binding property of the agonist was further strengthened by the observation that in rat cerebellum and rat renal papilla, where [125I]-IRL-1620 binding was irreversible, guanine nucleotides had no effect on the binding of this ligand. These data clearly indicate that there is a good correlation between the reversible binding property of the ET receptor agonist and the guanine nucleotide effect on the binding of the agonist.
    [Abstract] [Full Text] [Related] [New Search]