Effects of chronically elevated glucose levels on the functional properties of rat pancreatic beta-cells.

摘要: This study examines the effects of chronically elevated glucose levels on survival and function purified rat β-cells. Prolonged exposure (9 days) β-cell aggregates to 20 mmol/l did not lead cell losses, but reduced amount insulin secreted in response glucose. decrease was caused by cellular desensitization resulted from lower content after a prolonged imbalance between stimulated rates synthesis release. Virtually all β-cells exhibited state metabolic biosynthetic activation, which maintained for at least 2 h glucose-depleted media. Their protein were amplified glucose, reaching (half-) maximal stimulation concentrations (2 5 mmol/l, respectively) than control cells cultured 10 (5 respectively). As release, net effect markedly as compared with that cells. also case culture 6 In latter condition, glucose-inducible activities desensitization, 50% unresponsive other responding sensitivity (half-maximal 7 glucose). Comparison three indicated increases number degranulated cells, high proportion immature granules, glycogen deposition-morphologic features previously described conditions hyperglycemia. It is concluded chronic induces activation hypersensitivity rather glucotoxicity or desensitization. shift functional population responsible release observed levels.