Effect of the pyridoindole antioxidant stobadine on the cardiac Na⁺,K⁺-ATPase in rats with streptozotocin-induced diabetes

Rok, strany: 2006, 111 - 124

In the present study we examined the effect of dietary supplementation with the pyridoindole antioxidant stobadine on functional properties of the cardiac Na⁺,K⁺-ATPase in diabetic rats. Diabetes lasting sixteen weeks which was induced by a single i.v. dose of streptozotocin (55 mg·kg^-1) was followed by decrease in the enzyme activity. Evaluation of kinetic parameters revealed a statistically significant decrease in the maximum velocity (Vmax) (32% for ATP-activation, 33% for Na⁺-activation), indicating a diabetes-induced diminution of the number of active enzyme molecules in cardiac sarcolemma. The ATP-binding properties of the enzyme were not affected by diabetes as suggested by statistically insignificant changes in the value of Michaelis-Menten constant, KM (ATP). On the other hand, the affinity to sodium decreased as suggested by 54% increase in the KM (Na+) value. This impairment in the affinity of the Na⁺-binding site together with decreased number of active Na⁺,K⁺-ATPase molecules are probably responsible for the deteriorated enzyme function in hearts of diabetic animals. Administration of stobadine to diabetic rats dramatically improved the function of cardiac Na⁺,K⁺-ATPase with regard to Na⁺-handling, as documented by statistically significant elevation of Vmax by 66 and 47% decrease in KM (Na+). Our data suggest that stobadine may prevent the diabetes-induced deterioration of cardiac Na⁺,K⁺-ATPase, thus enabling to preserve its normal function in regulation of intracellular homeostasis of Na⁺ and K⁺ ions.

ISO 690:

Vlkovičová, J., Javorková, V., Stefek, M., Kyselova, Z., Gajdošíková, A., Vrbjar, N. 2006. Effect of the pyridoindole antioxidant stobadine on the cardiac Na⁺,K⁺-ATPase in rats with streptozotocin-induced diabetes. In General Physiology and Biophysics, vol. 25, no.2, pp. 111-124. 0231-5882.

APA:

Vlkovičová, J., Javorková, V., Stefek, M., Kyselova, Z., Gajdošíková, A., Vrbjar, N. (2006). Effect of the pyridoindole antioxidant stobadine on the cardiac Na⁺,K⁺-ATPase in rats with streptozotocin-induced diabetes. General Physiology and Biophysics, 25(2), 111-124. 0231-5882.