Sulfonylureas are drugs widely used in the treatment of patients with type 2 diabetes mellitus. In addition to their pancreatic effect stimulating insulin secretion many studies suggest that they also have extrapancreatic actions. We have previously reported that gliclazide, a second-generation sulfonylurea, stimulates the glucose uptake by rat hindquarter skeletal muscle directly and immediately by promoting the translocation of GLUT4 to the plasma membrane. The aim of our study was to approach the gliclazide intracellular signaling pathway. For this purpose we incubated clamped and isolated soleus muscle from rat with gliclazide. The following results were obtained: 1) Gliclazide stimulates IRS-1-PI3-kinase associated activity and this activity is necessary for gliclazide-stimulated glucose transport. 2) Gliclazide treatment produces a gradual translocation of DAG dependent isoforms PKC , and from cytosolic to membrane fraction that is dependent on PI3-kinase and PLC- activation 3) PKC and PLC- activation is necessary for gliclazide-stimulated glucose transport. We propose a hypothetical signaling pathway by which gliclazide could stimulate IRS-1 that would allow its association with PI3-kinase, promoting its activation. PI3-kinase products could induce PLC- activation whose hydrolytic activity could activate DAG dependent isoforms PKC , and .