Influence of sub-chronic diabetes mellitus on functional properties of renal Na(+),K(+)-ATPase in both genders of rats.
For characterization of Na(+),K(+)-ATPase, a key enzyme involved in maintenance of intracellular sodium homeostasis, expression of alpha1 subunit and the ATP- and Na(+)-binding properties were investigated by Western blot analysis and by enzyme kinetics, respectively. Previous studies documented time-dependent alteration of properties of renal Na(+),K(+)-ATPase from its mobilization after 8 days to serious deteriorations after 16 weeks of diabetes in rats. Characterizing the critical period during development of the disease, when mobilization of Na(+),K(+)-ATPase observed in the acute phase turns to its damage, we examined the enzyme properties after 8 weeks lasting diabetes which was induced by a single intraperitoneal administration of streptozotocin in a dose of 65 mg.kg(-1). The unchanged expression of Na(+),K(+)-ATPase alpha1-subunit in both genders indicates that 8 weeks represent the time when the mobilization of enzyme synthesis observed previously in acute diabetes is lost. In this time the renal Na(+),K(+)-ATPase undergoes structural changes in the vicinity of Na(+)-binding site resulting in worsened affinity to sodium in both genders as indicated by 13% and 18% increase of K(Na) value in female and male rats, respectively. However, gender specific was the diabetes-induced decrease in affinity to ATP by 18% which occurred in female rats only.
Javorková
Veronika
V
Institute for Heart Research, Department of Biochemistry, Slovak Academy of Sciences, 840 05 Bratislava 45, Slovakia.
Mézešová
Lucia
L
Vlkovičová
Jana
J
Vrbjar
Norbert
N
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D005260:Female; D007668:Kidney / Q000201:enzymology* / Q000473:pathology; D007700:Kinetics; D008297:Male; D009929:Organ Size; D011236:Prediabetic State / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D021122:Protein Subunits; D051381:Rats; D012727:Sex Characteristics; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors; D015430:Weight Gain
D001786:Blood Glucose; D021122:Protein Subunits; D000254:Sodium-Potassium-Exchanging ATPase