Insulin secretagogues, but not glucose, stimulate an increase in [Ca2+](i) in the fetal human and porcine beta-cell

Weinhaus, Anthony J., Tabiin, Muhammad T., Poronnik, Philip, Palma, Catalina A., Cook, David I. and Tuch, Bernard E. (2003) Insulin secretagogues, but not glucose, stimulate an increase in [Ca2+](i) in the fetal human and porcine beta-cell. Journal of Clinical Endocrinology and Metabolism, 88 6: 2753-2759. doi:10.1210/jc.2002-021542


Author Weinhaus, Anthony J.
Tabiin, Muhammad T.
Poronnik, Philip
Palma, Catalina A.
Cook, David I.
Tuch, Bernard E.
Title Insulin secretagogues, but not glucose, stimulate an increase in [Ca2+](i) in the fetal human and porcine beta-cell
Formatted title
Insulin Secretagogues, But Not Glucose, Stimulate an Increase in [Ca2+]i in the Fetal Human and Porcine ß-Cell
Journal name Journal of Clinical Endocrinology and Metabolism   Check publisher's open access policy
ISSN 0021-972X
Publication date 2003
Sub-type Article (original research)
DOI 10.1210/jc.2002-021542
Volume 88
Issue 6
Start page 2753
End page 2759
Total pages 7
Place of publication Bethesda
Publisher The Endocrine Society
Language eng
Subject 1114 Paediatrics and Reproductive Medicine
1103 Clinical Sciences
Abstract Fetal pancreatic beta-cells release insulin poorly in response to glucose; however, the cellular mechanism for this is unknown. By using fura-2 to measure changes in the cytoplasmic free Ca2+ concentration in beta-cells, we examined human/porcine fetal islet-like cell clusters (ICCs) and human adult islets for the presence of functional K-ATP(+) and voltage-activated Ca2+ ion channels. The effects of glucose, glyceraldehyde, leucine, KCl, and the channel effectors glipizide and BAY K8644 were studied. In fetal human/porcine ICCs and adult islets, KCl, glipizide, and BAY K8644 increased [Ca2+](i). Both glucose and glyceraldehyde increased [Ca2+](i) in islets but had no effect on ICCs. Leucine increased [Ca2+](i) in islets and porcine but not human ICCs. We hypothesize that the beneficial effect of leucine in fetal porcine, but not human ICCs, is attributable to time-dependent maturation of the beta-cells, because porcine ICCs examined were at 87% of the gestational period, and human ICCs were at 42%. Our data demonstrate that both K-ATP(+) and voltage-activated Ca2+ channels, required for glucose-stimulated increase in [Ca2+](i), are functional early in gestation. This suggests that the cause of the immaturity of fetal human/porcine beta-cells is at a more proximal step of glucose-induced metabolism than the channels on the cell surface.
Keyword Endocrinology & Metabolism
Pancreatic-islets
B-cells
Ca2+ Concentration
Rat Insulinoma
Cytosolic Ca2+
K+ Channels
Secretion
Calcium
Release
Atp
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Biomedical Sciences Publications
 
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Created: Wed, 19 Sep 2007, 16:39:31 EST