Comparative effects of efaroxan and beta-carbolines on the secretory activity of rodent and human beta cells
UNSPECIFIED (2003) Comparative effects of efaroxan and beta-carbolines on the secretory activity of rodent and human beta cells. In: 4th International Symposium on Agmatine and Imidazoline Systems, San Diego, CA, APR 09-11, 2003. Published in: AGMATINE AND IMIDAZOLINES: THEIR NOVEL RECEPTORS AND ENZYMES, 1009 pp. 167-174.Full text not available from this repository.
Official URL: http://dx.doi.org/10.1196/annals.1304.019
The pancreatic beta-cell expresses an imidazoline-binding site that is involved in the regulation of insulin secretion. This site is pharmacologically atypical in comparison with the I-1 and I-2 sites described in other tissues, and it has been classified as I-3. The structural requirements for binding of ligands to the I-3 site have not been fully defined, although a range of synthetic I-3 ligands have been characterized in functional terms. Evidence has been presented that an endogenous I-3 ligand may exist, because extracts of brain contain an active principle that stimulates insulin secretion in a manner consistent with the involvement of I-3 sites. The active component has not been identified but has been equated with the long-sought clonidine displacing substance (CDS) that is proposed as the endogenous ligand for imidazoline-binding sites. Recent evidence has indicated that one active component of CDS may be a beta-carboline, but it is not known whether beta-carbolines can stimulate insulin secretion. Thus, we have studied the effects of beta-carbolines on insulin secretion and cytosolic Ca2+ levels in rodent and human islet cells. The results reveal that harmane, pinoline, and norharmane cause a dose- and glucose-dependent increase in insulin secretion but show that this response differs in a number of ways from that elicited by the well-characterized I-3-agonist, efaroxan. Thus, beta-carbolines represent a new class of insulin secretagogues, although it remains unclear whether their action is mediated solely by I-3 sites in the beta cell.
|Item Type:||Conference Item (UNSPECIFIED)|
|Series Name:||ANNALS OF THE NEW YORK ACADEMY OF SCIENCES|
|Journal or Publication Title:||AGMATINE AND IMIDAZOLINES: THEIR NOVEL RECEPTORS AND ENZYMES|
|Publisher:||NEW YORK ACAD SCIENCES|
|Editor:||Piletz, JE and Regunathan, S and Ernsberger, P|
|Number of Pages:||8|
|Page Range:||pp. 167-174|
|Title of Event:||4th International Symposium on Agmatine and Imidazoline Systems|
|Location of Event:||San Diego, CA|
|Date(s) of Event:||APR 09-11, 2003|
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