title: Synergistic effect of glucose and prolactin on GLUT2 expression in cultured neonatal rat islets.
abstract: We studied the synergistic effect of glucose and prolactin (PRL) on insulin secretion and GLUT2 expression in cultured neonatal rat islets. After 7 days in culture, basal insulin secretion (2.8 mM glucose) was similar in control and PRL-treated islets (1.84 +/- 0.06% and 2.08 +/- 0.07% of the islet insulin content, respectively). At 5.6 and 22 mM glucose, insulin secretion was significantly higher in PRL-treated than in control islets, achieving 1.38 +/- 0.15% and 3.09 +/- 0.21% of the islet insulin content in control and 2.43 +/- 0.16% and 4.31 +/- 0.24% of the islet insulin content in PRL-treated islets, respectively. The expression of the glucose transporter GLUT2 in B-cell membranes was dose-dependently increased by exposure of the islet to increasing glucose concentrations. This effect was potentiated in islets cultured for 7 days in the presence of 2 micrograms/ml PRL. At 5.6 and 10 mM glucose, the increase in GLUT2 expression in PRL-treated islets was 75% and 150% higher than that registered in the respective control. The data presented here indicate that insulin secretion, induced by different concentrations of glucose, correlates well with the expression of the B-cell-specific glucose transporter GLUT2 in pancreatic islets.
authors.affiliation: Departamento de Educaçäo Física/Ciências Biológicas, Universidade Estadual Paulista, Bauru, SP, Brasil.
authors.forename: S C
authors.initials: SC
authors.lastname: Crepaldi-Alves
authors.forename: E M
authors.initials: EM
authors.lastname: Carneiro
authors.forename: J R
authors.initials: JR
authors.lastname: Bosqueiro
authors.forename: A C
authors.initials: AC
authors.lastname: Boschero
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D005947:Glucose / Q000502:physiology*; D051273:Glucose Transporter Type 2; D007515:Islets of Langerhans / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis*; D011388:Prolactin / Q000502:physiology*; D051381:Rats
chemical_list: D051273:Glucose Transporter Type 2; D009004:Monosaccharide Transport Proteins; D011388:Prolactin; D005947:Glucose