Abstract:

Objective To investigate the effects of dehydroepiandrosterone-sulfate (DHEAS) on glucose-stimulated insulin secretion in pancreatic islets β cell lines (MIN6). Methods MIN6 cells at exponential phase of growth stimulated by glucose (2.8 mmol/L and 16.7 mmol/L) were served as study objectives. Cells were treated by DHEAS (1, 5 and 10 μmol/L) for 10 min and 24 h (1 μmol/L DHEAS group, 5 μmol/L DHEAS group and 10 μmol/L DHEAS group), and DHEAS group (treated by 5 μmol/L DHEAS for 24 h) and DHEAS+RU486 group (treated by 5 μmol/L DHEAS+10 μmol/L glucocorticoid receptor blocker RU486 for 24 h) were divided. Besides, blank control group was established. The insulin secretion in the supernatant was measured by ELISA method, and the expression of insulin mRNA was detected by Real-Time PCR. Results After treatment for 10 min and 24 h, the insulin secretion of MIN6 cells in the supernatant in 5 μmol/L DHEAS group and 10 μmol/L DHEAS group was significantly higher than that in blank control group （P<0.05）. After treatment for 24 h, there was no significant difference in insulin secretion of MIN6 cells in the supernatant between DHEAS+RU486 group and DHEAS group (P>0.05), while both were significantly higher than that in blank control group (P<0.05). After treatment for 24 h, the expression of insulin mRNA of MIN6 cells in 5 μmol/L DHEAS group and 10 μmol/L DHEAS group was significantly higher than that in blank control group (P<0.05). Conclusion The glucose-stimulated insulin secretion of MIN6 cells could be promoted by DHEAS, which may be mediated by an unidentified nuclear receptor but not glucocorticoid receptor.

Key words: dehydroepiandrosterone-sulfate, pancreatic &beta, cells, glucose-stimulated insulin secretion