title: Co-expression and regulation of connexins 36 and 43 in cultured neonatal rat pancreatic islets.
abstract: Fetal and neonatal pancreatic islets present a lower insulin secretory response as compared with adult islets. Prolonged culturing leads to an improvement of the glucose-induced insulin secretion response in neonatal pancreatic islets that may involve regulation of gap junction mediated cell communication. In this study, we investigated the effect of culturing neonatal islet cells for varying periods of time and with different glucose medium concentrations on the cellular expression of the endocrine pancreatic gap junction associated connexin (Cx) 36 and Cx43. We report here that the 7-d culture induced upregulation of the expression of these junctional proteins in neonatal islets in a time-dependent manner. A correlation was observed between the increased mRNA and protein expression of Cx36 and Cx43 and the increased insulin secretion following islet culturing. In addition, increasing glucose concentration within the culture medium induced a concentration-dependent enhancement of Cx36 islet expression, but not of Cx43 expression in cultured neonatal islets. In conclusion, we suggest that the regulation of gap junctional proteins by culture medium containing factors and glucose may be an important event for the maturation process of beta cells observed at in vitro conditions.
authors.affiliation: Department of Physiology and Biophysics, Universidade Estadual de Campinas, Brasil.
authors.forename: A R
authors.initials: AR
authors.lastname: Leite
authors.forename: C P F
authors.initials: CP
authors.lastname: Carvalho
authors.forename: A G
authors.initials: AG
authors.lastname: Furtado
authors.forename: H C L
authors.initials: HC
authors.lastname: Barbosa
authors.forename: A C
authors.initials: AC
authors.lastname: Boschero
authors.forename: C B
authors.initials: CB
authors.lastname: Collares-Buzato
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D018031:Connexin 43 / Q000096:biosynthesis* / Q000235:genetics; D017630:Connexins / Q000096:biosynthesis* / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D015854:Up-Regulation; D000097004:Gap Junction delta-2 Protein
chemical_list: D018031:Connexin 43; D017630:Connexins; D005947:Glucose; D007328:Insulin; D012333:RNA, Messenger; D000097004:Gap Junction delta-2 Protein