Synergistic effect of glucose and prolactin on GLUT2 expression in cultured neonatal rat islets

• Published in: Brazilian journal of medical and biological research Vol. 30; no. 3; pp. 359 - 361
• Main Authors: Crepaldi-Alves, S C, Carneiro, E M, Bosqueiro, J R, Boschero, A C
• Format: Journal Article
• Language: English
• Published: Brazil Associação Brasileira de Divulgação Científica 01-03-1997
• Subjects: Animals; BIOLOGY; Cell Culture Techniques; glucose; Glucose - physiology; glucose transporter; Glucose Transporter Type 2; Islets of Langerhans - metabolism; MEDICINE, RESEARCH & EXPERIMENTAL; Monosaccharide Transport Proteins - biosynthesis; pancreatic islets; prolactin; Prolactin - physiology; Rats; glucose; prolactin; glucose transporter; pancreatic islets
• ISSN: 0100-879X; 1414-431X; 0100-879X; 1414-431X
• DOI: 10.1590/s0100-879x1997000300008

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.