Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/3894
Title: Glucose-mediated Ca2+ signalling in single clonal insulin-secreting cells: evidence for a mixed model of cellular activation
Authors: Salgado, António P. 
Santos, Rosa M. 
Fernandes, Ana P. 
Tomé, Angelo R. 
Flatt, Peter R. 
Rosário, Luís M. 
Keywords: Pancreatic [beta]-cell line; Glucose metabolism; Ca2+ oscillations; Fura-2 fluorescence; Cellular heterogeneity
Issue Date: 2000
Citation: The International Journal of Biochemistry & Cell Biology. 32:5 (2000) 557-569
Abstract: Using clonal insulin-secreting BRIN-BD11 cells, we have assessed whether the graded response of the whole cell population to glucose can be accounted for by a dose-dependent recruitment of individual cells, an amplification of the response of the recruited cells or both. Cytosolic free Ca2+ concentration ([Ca2+]i) is an established index of [beta]-cell function. We used fura-2 microfluorescence techniques to assess the [Ca2+]i responsiveness of single BRIN-BD11 cells to glucose and other secretagogues. Glucose (1-16.7 mM) evoked oscillatory [Ca2+]i rises in these cells resembling those found in parental rat pancreatic [beta]-cells. The percentage of glucose-responsive cells was 11% at 1 mM and increased to 40-70% at 3-16.7 mM glucose, as assessed by a single-stimulation protocol. This profile was unrelated to possible differences in the cell cycle, as inferred from experiments where the cultured cells were synchronized by a double thymidine block protocol. Individual cells exhibited variable sensitivities to glucose (threshold range: 1-5 mM) and a variable dose-dependent amplification of the [Ca2+]i responses (EC50 range: 2-10 mM), as assessed by a multiple-stimulation protocol. Glyceraldehyde and [alpha]-ketoisocaproic acid had glucose-like effects on [Ca2+]i. The data support a mixed model for the activation of insulin-secreting cells. Specifically, the graded secretory response of the whole cell population is likely to reflect both a recruitment of individual cells with different sensitivities to glucose and a dose-dependent amplification of the response of the recruited cells.
URI: http://hdl.handle.net/10316/3894
Rights: openAccess
Appears in Collections:FCTUC Ciências da Vida - Artigos em Revistas Internacionais

Files in This Item:
File Description SizeFormat
filefcdac3dafe3e43c0827329b507ebca0a.pdf505.98 kBAdobe PDFView/Open
Show full item record

Page view(s)

136
checked on Oct 16, 2019

Download(s)

60
checked on Oct 16, 2019

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.