Objective:To investigate the change of [Ca2+]i in type 2 diabetes mellites patients and its relationship with insulin receptor tyrosine kinase activity. Methods: The [Ca2+]i was assayed with fluorescence spectroscopic analysis and the insulin receptor tyrosine kinase activity was assayed with enzyme-linked immunosorbent assay method in circulating mononuclear cells in 40 type 2 diabetes mellites patients and 20 normal subjects. Results:The [Ca2+]i of circulating mononuclear cells in type 2 diabetes mellites patients was significantly higher than that in normal controls. The insulin receptor tyrosine kinase activity was significantly decreased in patients. The [Ca2+]i of circulating mononuclear cells in type 2 diabetes mellites patients was positively correlated with FBG

FINS

and negatively with the insulin receptor tyrosine kinase activity. Conclusion: The results suggest that elevation of [Ca2+]i may affect the insulin receptor tyrosine kinase activity and thus contributes to the insulin resistance.