Reversal of Glucose Insensitivity of Pancreatic B-Cells Due to Prolonged Exposure to High Glucose in Culture: Effect of Nicotinamide on Pancreatic B-Cells.

Abstract

OHGAWARA, H., KAWAMURA, M., HONDA, M., KARIBE, S., IWASAKI, N., TASAKA, Y. and OMORI, Y. Reversal of Glucose Insensitivity of Pancreatic B-Cells Due to Prolonged Exposure to High Glucose in Culture: Effect of Nicotinamide on Pancreatic B-Cells. Tohoku J. Exp. Med., 1993, 169 (2), 159-166 Prolonged in vitro exposure to high glucose has been shown to induce a decrease in pancreatic B-cell sensitivity to glucose stimulation. This experiment was designed to study whether nicotinamide affects the B-cells' response to regulatory stimuli of glucose after prolonged culture with high glucose. Neonatal pig pancreatic islet-like cell clusters (ICCs) formed from single cells were embedded in agarose-gel. Some of them were maintained in RPMI 1640 containing a high glucose concentration (16.7 mM) and 10% fetal bovine serum (FBS) with or without nicotinamide. Then, the embedded-ICCs were stimulated by glucose at concentrations of 5.5mM and 16.7 mM. After the prolonged culture with high glucose, the ICCs showed no response to acute glucose stimulation. There was a significant increase in glucose-mediated insulin secretion when the ICCs were maintained with the medium containing nicotinamide. We conclude that nicotinamide could protect B-cell desensitization to glucose after prolonged exposure to high glucose. - desensitization to glucose; pancreatic islet; ICCs; agarose; embedded-culture