[Effect of berberine on insulin secretion and glucokinase activity of NIT-1 cells].

ABSTRACT

To investigate the effect of berberine on insulin secretion of NIT-1 cells stimulated by glucose and the possible molecular mechanism, we used radioimmunoassay, scintillation counting technique, enzymatic method and Western blotting to measure the effects of berberine on insulin secretion, glucose utilization, the activity of glucokinase (GK) and protein level of GK and GK regulation protein (GKRP). Compared with untreated group, insulin secretion level, glucose utilization, the activity and protein level of GK in NIT-1 cells stimulated by high concentration of glucose were increased significantly in berberine group (P < 0.05), while the protein level of GKRP in berberine group decreased markedly. In conclusion, berberine can promote insulin secretion of NIT-1 cells induced by high concentration of glucose. The possible molecular mechanism may be associated with berberine acting as a GK activator, improving glucose utilization, enhancing the activity and protein expression level of GK, as well as decreased the protein level of GKRP.