[Frontiers in Bioscience 7, d752-764, March 1, 2002]

PEROXYNITRITE ACTIVATES GLUCOSE UPTAKE IN 3T3-L1 ADIPOCYTES THROUGH A PI3-K-DEPENDENT MECHANISM

Alberto M. Guzman-Grenfell 1, Rebeca Garcia-Macedo 2, Marco T. Gonzalez-Martinez 3, Juan Jose Hicks 1 and Rafael Medina-Navarro 2

1 Laboratorio de Bioquimica Inorganica, Direccion de Investigacion, Instituto Nacional de Enfermedades Respiratorias. Mexico, D.F. Mexico, 2 Unidad de Investigacion Medica en Bioquimica, Hospital de Especialidades del Centro Medico Nacional Siglo XXI. Instituto Mexicano del Seguro Social. Mexico, D.F., 3 Departamento de Farmacologia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico. Mexico, D.F.

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1.Materials
3.2.Cell culture and peroxynitrite treatment
3.3.Glucose transport and cell viability
3.4.Intracellular ATP determination
3.5. Immunoprecipitations and Western Blotting
3.6. Statistical analysis
4. Results
4.1.Effect of peroxynitrite on cell viability
4.2.Effect of peroxynitrite on glucose transport
4.3.Lack of effect of ATP and calcium ions on peroxynitrite-induced glucose uptake
4.4.Effect of PI3-K inhibition on the peroxynitrite-induced glucose uptake
5. Discussion
6. Acknowledgements
7. References

1. ABSTRACT

Peroxynitrite, the product of the reaction between .NO and O2.-, is a strong oxidant and nitrating molecule, and it has been recently consideredas a component of some important signaling pathways. Herein, we report the effect of peroxynitrite on glucose uptake in 3T3-L1 adipocytes. Peroxynitrite stimulated glucose uptake and this effect was inhibited by citochalasin B, indicating the participation of facilitated GLUT transporters. Peroxynitrite-induced glucose uptake was not related to intracellular ATP, nor to external or internal calcium, but it was inhibited by the phosphatidylinositol 3-kinase (PI3-K) inhibitor, wortmannin. Additionally, we also found that peroxynitrite did not activate the insulin receptor nor the PI3-K downstream signaling protein kinase B (PKB/Akt). The dose-dependent inhibitory action of wortmannin suggests that peroxynitrite activates glucose transport without affecting GLUT transporters translocation.