摘要
AIM： To observe the effect of berberine on insulin secretion in rat pancreatic islets and to explore its possible molecular mechanism. METHODS： Pdmary rat islets were isolated from male Sprague-Dawley rats by collagenase digestion and treated with different concentrations （1, 3, 10 and 30 μmol/L） of berberine or 1 μmol/L Glibenclamide （GB） for 24 h. Glucose-stimulated insulin secretion （GSIS） assay was conducted and insulin was determined by radioimmunoassay. 3-（4,5-Dimethylthiazol-2-yl）- 2,5-diphenyltetrazolium bromide （MTT） assay was performed to evaluate cytotoxicity. The mRNA level of hepatic nuclear factor 4 alpha （HAIF4α） was determined by reverse transcription polymerase chain reaction （RT-PCR）. Indirect immunofluorescence staining and Western blot analysis were employed to detect protein expression of HNF4α in the islets. Glucokinase （GK） activity was measured by spectrophotometric method. RESULTS： Berberine enhanced GSIS rather than basal insulin secretion dose-dependently in rat islets and showed no significant cytotoxicity on islet cells at the concentration of 10 μmol/L. Both mRNA and protein expressions of HNF4α were up-regulated by berberine in a dose-dependent manner, and GK activity was also increased accordingly. However, GB demonstrated no regulatory effects on HNF4α expression or GK activity. CONCLUSION： Berberine can enhance GSIS in rat islets, and probably exerts the insulinotropic effect via a pathway involving HNF4α and GK, which is distinct from sulphonylureas （SUs）.
AIM: To observe the effect of berberine on insulin secretion in rat pancreatic islets and to explore its possible molecular mechanism. METHODS: Primary rat islets were isolated from male Sprague-Dawley rats by collagenase digestion and treated with different concentrations (1,3,10 and 30 μmol/L) of berberine or 1 μmol/L Glibenclamide (GB) for 24 h. Glucose-stimulated insulin secretion (GSIS) assay was conducted and insulin was determined by radioimmunoassay. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate cytotoxicity. The mRNA level of hepatic nuclear factor 4 alpha (HNF4α) was determined by reverse transcription polymerase chain reaction (RT-PCR). Indirect immunofluorescence staining and Western blot analysis were employed to detect protein expression of HNF4α in the islets. Glucokinase (GK) activity was measured by spectrophotometric method. RESULTS: Berberine enhanced GSIS rather than basal insulin secretion dose-dependently in rat islets and showed no significant cytotoxicity on islet cells at the concentration of 10 μmol/L. Both mRNA and protein expressions of HNF4α were up-regulated by berberine in a dose-dependent manner,and GK activity was also increased accordingly. However,GB demonstrated no regulatory effects on HNF4α expression or GK activity. CONCLUSION: Berberine can enhance GSIS in rat islets,and probably exerts the insulinotropic effect via a pathway involving HNF4α and GK,which is distinct from sulphonylureas (SUs).
基金
The National Natural Science Foundation of China,No.30500685
作者简介
Correspondence to： Dr. Fu-Er Lu, Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China. felu@tjh.tjmu.edu.cn Telephone： ＋86-27-83663237 Fax： ＋86-27-83663237
