Does cellular glucose transport respond to a controlled diet and sulfonylurea therapy in type 2 diabetes mellitus?

Abstract

Introduction: The normalization of cellular glucose assimilation is the basic aim of therapy in diabetes mellitus. This process should be accompanied by a proportional increase of the cellular glucose transport (CGT). The level of CGT should react to therapy typically recommended in Type 2 diabetes mellitus (T2DM), composed of diet and sulfonylurea. In order to explore this clinically significant hypothesis, a clinical-experimental study was undertaken. Its aim was to determine the clinical pharmacotherapeutic significance of CGT measurements.
Material and methods: CGT testing was performed on peripheral blood lymphocytes. CGT was assessed with 2-[³H(G)] glucose: before, and after the addition of sulfonylurea or sulfonylurea plus insulin to the incubation medium. Tests were performed at baseline in 28 persons with newly diagnosed, "therapeutically naive" T2DM and in 20 control subjects. In diabetic patients the tests for CGT were repeated after 3 months of routine diet and sulfonylurea therapy. In addition, the level of GLUT4 expression was assessed by flow cytometry before and after this therapy.
Results: Before treatment, CGT was significantly decreased in all subjects with T2DM. Incubated in-vitro cells responded directly to the addition of sulfonylurea with a moderate increase of CGT. This response was augmented by the addition of insulin to sulfonylurea in the incubation medium. The monitored three-month routine, controlled therapy with diet and sulfonylurea resulted in a significant increase of CGT process in all types of incubation tests.
Conclusions: The basal and reactive CGT is significantly decreased in lymphocytes of persons with T2DM before the introduction of therapy. Effective therapy with diet and sulfonylurea normalizes both types of CGT - basal and reactive. It is related to the near normalization of GLUT4 expression in the studied cells. This phenomenon may be used as a new marker for diabetes mellitus pharmacotherapy.
(Pol J Endocrinol 2010; 61 (1): 75-81)