Beta cell coupling and connexin expression change during the functional maturation of rat pancreatic islets

Carvalho, C P. F.; Barbosa, H C. L.; Britan, Aurore; Santos-Silva, J C. R.; Boschero, A. C.; Meda, Paolo; Collares-Buzato, C. B.

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Title		Beta cell coupling and connexin expression change during the functional maturation of rat pancreatic islets
Authors		Carvalho, C P. F. Barbosa, H C. L. Britan, Aurore Santos-Silva, J C. R. Boschero, A. C. Meda, Paolo Collares-Buzato, C. B.
Published in		Diabetologia. 2010, vol. 53, no. 7, p. 1428-1437
Abstract		AIMS/HYPOTHESIS: Cell-cell coupling mediated by gap junctions formed from connexin (CX) contributes to the control of insulin secretion in the endocrine pancreas. We investigated the cellular production and localisation of CX36 and CX43, and gap junction-mediated beta cell coupling in pancreatic islets from rats of different ages, displaying different degrees of maturation of insulin secretion. METHODS: The presence and distribution of islet connexins were assessed by immunoblotting and immunofluorescence. The expression of connexin genes was evaluated by RT-PCR and quantitative real-time PCR. The ultrastructure of gap junctions and the function of connexin channels were assessed by freeze-fracture electron microscopy and tracer microinjection, respectively. RESULTS: Young and adult beta cells, which respond to glucose, expressed significantly higher levels of Cx36 (also known as Gjd2) than fetal and newborn beta cells, which respond poorly to the sugar. Accordingly, adult beta cells also showed a significantly higher membrane density of gap junctions and greater intercellular exchange of ethidium bromide than newborn beta cells. Cx43 (also known as Gja1) was not expressed by beta cells, but was located in various cell types at the periphery of fetal and newborn islets. CONCLUSIONS/INTERPRETATION: These findings show that the pattern of connexins, gap junction membrane density and coupling changes in islets during the functional maturation of beta cells.
Keywords		Animals — Animals, Newborn — Connexin 43/genetics/metabolism — Connexins/genetics/metabolism — Female — Fluorescent Antibody Technique — Gap Junctions/metabolism — Immunoblotting — Insulin-Secreting Cells/metabolism/ultrastructure — Islets of Langerhans/growth & development/*metabolism/ultrastructure — Male — Microscopy, Electron — Rats — Rats, Wistar — Reverse Transcriptase Polymerase Chain Reaction
Identifiers		DOI: 10.1007/s00125-010-1726-8 PMID: 20361177
Full text		Article - Limited access to UNIGE Other version: http://www.springerlink.com/content/a638854732252019/fulltext.pdf
Structures		Faculté de médecine / Section de médecine fondamentale / Département de physiologie cellulaire et métabolisme
Research group		Couplage cellulaire et connexines (136)
Citation (ISO format)		CARVALHO, C P. F. et al. Beta cell coupling and connexin expression change during the functional maturation of rat pancreatic islets. In: Diabetologia, 2010, vol. 53, n° 7, p. 1428-1437. https://archive-ouverte.unige.ch/unige:20824