胰岛素对β细胞胰岛素分泌的反馈影响

目的：探讨不同浓度外源性胰岛素在不同浓度葡萄糖情况下对β TC-3细胞胰岛素分泌的影响。方法：取对数生长期的13TC3细胞分三组，即低糖组、中糖组、高糖组（葡萄糖浓度分别取1．0mmol／L、3．Ommoi／L、20．Ommol／L）。每组分0、5、10、15、100、500、5000和50000μU／ml胰岛素八个亚组（其中0μU／ml作为对照组）。刺激10分钟后取上清液测C肽。结果：在高糖组中，C肽分泌量无明显差异；在中糖组中，10μU／ml和15μU／ml两组相对对照组C肽分泌量显著增加，50000μU／ml组C肽分泌量则相对对照组出现减少，其余3个亚组无明显改变；在低糖组中，c肽分泌量除5000μU／ml组减少外。其它亚组C肽分泌量无明显差畀。结论：胞外胰岛素在适宜葡萄糖浓度时，对BTC3细胞胰岛素分泌的反馈影响呈剂量依赖关系。

Freeback Effects of Insulin on Insulin Secretion in Beta Cells

Objective： To investigate the effects of different concentrations of glucose and insulin on Glucose-stimulated insulin secretion of β TC-3 cells. Methods： β TC-3 cells in exponential phase of growth were divided into three groups： low sugar group （1.0mmol/L）, middle sugar group （3.0mmol/L）, and high sugar group （20.0mmol/L）. Each group were subdivided into eight subgroups, with different concentrations of insulin（0, 5, 10, 15, 100, 500, 5000 and 50000m U/ml）, taking the subgroup of 0 m U/ml as control. After stimulated for 10 minutes, supernate of each subgroup were collected to detect the c-peptide. Results： In high sugar groups, secretions of C-peptide were similar with no obvious difference. In middle sugar groups, secretion of C-peptide in 10m U/ml and 15m U/ml subgroups were obviously increased, while that in 50000 mU/ml subgroup was reduced, compared with the control group; no obvious changes were found in other three subgroups. In low sugar groups, secretion of C-peptide was reduced only in 5000mU/ml subgroup, and other subgroups showed no obvious changes. Conclusion： When the extracellular insulin is in suitable glucose concentration, the effect of insulin on glucose-stimulated insulin secretion is dose-dependent.