Effect of the pyridoindole antioxidant stobadine on ATP-utilisation by renal Na,K-ATPase in rats with streptozotocin-induced diabetes.
The effect of the pyridoindole antioxidant stobadine on diabetes-induced changes of Na,K-ATPase, especially those concerning the utilisation of its substrate ATP, was investigated. Sixteen weeks of streptozotocin-induced diabetes (single i.v. dose of streptozotocin; 55 mg/kg) was followed by decrease in the enzyme activity. This effect was emphasised in the presence of higher concentrations of substrate and in the presence of 8 mmol x l(-1) ATP it represented 20%. It might be a consequence of altered functional properties of Na,K-ATPase as suggested by 20% decrease in the V(max) value along with decrease in the K(m) value by 20%. Administration of 0.05% (w/w) stobadine in the diet to diabetic rats improved the function of renal Na,K-ATPase with respect to utilisation of ATP as suggested by significant increase in the enzyme activity in the whole concentration range of ATP investigated as a consequence of V(max) elevation to the level comparable to absolute controls. In conclusion, stobadine may play a positive role in restoring the functional properties of renal Na,K-ATPase, especially concerning the utilisation of energy derived from hydrolysis of ATP, improving thus the maintenance of ionic homeostasis during diabetes.
Vrbjar
N
N
Institute for Heart Research, Department of Biochemistry, Slovak Academy of Sciences, 840 05 Bratislava 45, P.O.Box 104, Slovakia. usrdnorb@savba.sk
Strelková
S
S
Javorková
V
V
Vlkovicová
J
J
Mézesová
L
L
Stefek
M
M
Kysel'ová
Z
Z
Gajdosíková
A
A
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage; D002243:Carbolines / Q000008:administration & dosage*; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D007211:Indoles / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013311:Streptozocin
D000975:Antioxidants; D002243:Carbolines; D007211:Indoles; D013311:Streptozocin; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase; C100106:dicarbine