Abstract: Objective To explore the chronic effect of excess palmitate on INS-1E cells and isolated mouse islets. Methods Islets were isolated by the collagenase digestion technique from adult NMRI mice. Both passaged INS-1E cells and isolated mouse islets were incubated in RPMI 1640 supplemented with 0 or 0.4 mmol/L palmitate for 72 h, respectively. After preincubation, both INS-1E cells and islets were incubated in Krebs-Ringer buffer containing 3.3 or 16.7 mmol/L glucose for 1 h, respectively. Correspondingly upper medium was taken for insulin assay. Total RNA was extracted from INS-1E cells after 72 h incubation with 0 or 0.4 mmol/L palmitate, cDNA was synthesized, Pdx1, Insulin 1, Insulin 2, and GLUT2 mRNA expressions were tested in INS-1E cells by RT-PCR. Results Basal insulin secretion was increased, and glucose-stimulated insulin secretion was impaired in both INS-1E cells and isolated mouse islets after long-term excess palmitate incubation, and insulin 1, insulin 2, and GLUT2 mRNA levels were diminished in INS-1E cells. Conclusion Long-term exposure to higher level of palmitate concentration may cause dysfunction of pancreatic islet cells.

Key words: lipotoxicity, B cell, gene