Prolonged Sulfonylurea Treatment Has No Effect on Lymphocyte Pc-1 Expression in Patients with Type 2 Diabetes Mellitus

Plasma cell antigen (PC-1) is an inhibitor of insulin receptor tyrosine kinase, which plays an important role in insulin resistance pathogenesis in type 2 diabetes mellitus, obesity and some other insulin resistant states. In a recent study we have demonstrated an increased lymphocyte PC-1 activity in patients with type 2 diabetes and its reversal by 3-month metformin treatment, corresponding to the improvement of insulin sensitivity. The aim of this study was to investigate the effect of prolonged treatment with two commonly used sulfonylurea agents, gliclazide and glibenclamide, on lymphocyte PC-1 expression. Twenty-six newly diagnosed, obese type 2 diabetes patients with a body mass index >30, and 14 healthy controls were enrolled in the study. Basal, concanavalin A (Con A)-stimulated, and phorbol-12-myristate-13-acetate (PMA)stimulated lymphocyte PC-1 was determined in 26 diabetic patients before and after 3-month of gliclazide (12 patients) and glibenclamide (14 patients) treatment. Fasting plasma glucose and blood fructosamine decreased significantly after treatment. Pre-treatment lymphocyte PC-1 activity in diabetic patients was significantly higher than in controls. Treatment with gliclazide or glibenclamide did not produced any significant effect in unstimulated, Con A-stimulated or PMA-stimulated PC-1 activity. In conclusion, this study has confirmed an increased lymphocyte PC-1 activity in type 2 diabetes. However, in contrast to the metformin action, prolonged treatment with two commonly used sulfonylurea agents, gliclazide and glibenclamide, did not produce any significant effect on lymphocyte PC-1. This study has established that sulfonylurea drugs have no effect on PC-1.