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.
Institute for Heart Research, Department of Biochemistry, Slovak Academy of Sciences, 840 05 Bratislava 45, P.O.Box 104, Slovakia. usrdnorb@savba.sk
N
N
Vrbjar
S
S
Strelková
V
V
Javorková
J
J
Vlkovicová
L
L
Mézesová
M
M
Stefek
Z
Z
Kysel'ová
A
A
Gajdosíková
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