TUBULIN IN THE REGULATION OF GLUCOSE REDUCTASE AND NA+, K+-ATPASE IN RATS WITH INDUCED DIABETES

RIVELLI J.F.; AMAIDEN M.R.; CAMPETELLI A.; PREVITALI G.; FOSSATTI F; ARCE C; CASALE C,H.

Villa Carlos Paz

Congreso; 44 Annual Meeting Argentine Society for Biochemistry and Molecular Biology Research - XLIV Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

CB-P16.TUBULIN IN THE REGULATION OF GLUCOSEREDUCTASE AND NA+, K+-ATPASE IN RATS WITHINDUCED DIABETESRivelli JF1, Amaiden MF1, Campetelli AN1, Previtalli G1, FossatiFA2, Arce CA3, Casale CH1.1Dpto. Biol. Molec. UNRC. 2Hospital Regional de Río Cuarto.3CIQUIBIC-UNC. E-mail: jrivelli@exa.unrc.edu.arPart of cytosolic tubulin is associated to plasma membrane andinhibit the Na+, K+-ATPase. We demonstrated that the ATPaseinhibition by tubulin in vitro is reverted by glutamate and reversiblyinhibited by glucose. In erythrocytes of diabetics patients (DP), theNa+, K+-ATPase is inhibited. To determinate if tubulin is involvedin the inhibition of the enzyme in these patients, we studied theplasma membrane tubulin of DP?s erythrocytes. Recently wedemonstrated that erythrocytes of DP have increased more than twofold the content of membrane tubulin. Similar results were foundwhen COS or CAD cells were incubated with glucose or sorbitol.This study demonstrate that the membrane tubulin increasessignificantly in brain of streptozotocin induced diabetic rats or ratstreated with an intraperitoneal injection of sorbitol. This increase iscorrelated with a decrease in Na+, K+-ATPase activity. The originof the sorbitol in DP is due to the reduction of glucose by glucosereductase, therefore we decided to study whether the tubulin hadany influence on the activity of this enzyme. Cytosolic extractsfrom rat brain were incubated with a tubulin preparation of the sametissue. The results show that tubulin is able to inhibit glucosereductase in vitro. These results show that tubulin could be involvedin regulating glucose reductase and Na+, K+-ATPase activities ofDP.