| Stimulation of insulin secretion by imidazoline compounds is not due to interaction with non-adrenoceptor idazoxan binding sites. | |
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MedLine Citation:
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PMID: 8095415 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. The potency of interaction of several imidazoline compounds with non-adrenoceptor idazoxan binding sites (NAIBS) in rat liver membranes was compared with their ability to alter insulin secretion from rat pancreatic islets. 2. NAIBS could be labelled specifically with [3H]-idazoxan in both rat liver membranes and in rat islet homogenates. Liver binding sites exhibited a KD for [3H]-idazoxan of 24 nM and a Bmax of 264 fmol mg-1 protein. 3. Binding of [3H]-idazoxan to NAIBS in rat liver membranes was displaced effectively by unlabelled idazoxan (IC50 0.1 microM) and by UK14304 (IC50 0.5 microM). However, two other imidazoline compounds efaroxan and RX821002, which are related in structure to idazoxan, were much less effective as displacers. 4. In insulin secretion experiments, the ATP-sensitive potassium channel agonist diazoxide (250 microM) was able to suppress the rise in insulin secretion induced by 20 mM glucose. Both efaroxan and RX821002 (100 microM) antagonized the inhibitory effect of diazoxide on glucose-induced insulin secretion. By contrast, neither idazoxan (100 microM) nor UK14304 (50 microM), was able to overcome significantly the inhibitory effect of diazoxide. 5. The ability of 100 microM efaroxan to antagonize the suppression of insulin secretion mediated by diazoxide, was not prevented by idazoxan (up to 100 microM) or by UK14304 (up to 50 microM). 6. The results indicate that the stimulatory effects of imidazoline compounds on insulin secretion are not due to interaction with NAIBS similar to those present in rat liver. |
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Authors:
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C A Brown; A C Loweth; S A Smith; N G Morgan |
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Publication Detail:
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Type: Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: British journal of pharmacology Volume: 108 ISSN: 0007-1188 ISO Abbreviation: Br. J. Pharmacol. Publication Date: 1993 Feb |
Date Detail:
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Created Date: 1993-04-09 Completed Date: 1993-04-09 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 7502536 Medline TA: Br J Pharmacol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 312-7 Citation Subset: IM |
Affiliation:
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Department of Biological Sciences, Keele University, Staffs. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic alpha-Agonists
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pharmacology Adrenergic alpha-Antagonists / pharmacology Animals Binding Sites / drug effects Imidazoles / pharmacology* Insulin / secretion* Islets of Langerhans / drug effects*, metabolism, secretion Liver / drug effects*, metabolism Male Membranes / drug effects, metabolism Radioligand Assay Rats Rats, Wistar Receptors, Adrenergic, alpha / drug effects* Receptors, Drug / drug effects* |
| Grant Support | |
ID/Acronym/Agency:
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//Wellcome Trust |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic alpha-Agonists; 0/Adrenergic alpha-Antagonists; 0/Imidazoles; 0/Receptors, Adrenergic, alpha; 0/Receptors, Drug; 0/idazoxan receptor; 11061-68-0/Insulin |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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