Kaločayová B, Mézešová L, Barteková M, Vlkovičová J, Jendruchová V, Vrbjar N
Institute for Heart Research, Slovak Academy of Sciences, Dúbravska cesta 9, 842 33, Bratislava, Slovak Republic.
Mol Cell Biochem. 2015 Jul;405(1-2):41-52. doi: 10.1007/s11010-015-2394-2. Epub 2015 Apr 18.
Time sequence study was performed to characterize the effects of diabetes mellitus type 1 on properties of the Na, K-ATPase in cerebral cortex derived from normal and streptozotocin (STZ)-diabetic rats of both genders. The samples were excised at varying time intervals of diabetes induced by STZ (65 mg kg(-1)) for 8 days, and 8 and 16 weeks. Expression of α1-3 isoforms of Na, K-ATPase was not altered in statistically significant level during all stages of diabetes neither in female nor in male rats as revealed from Western blot analysis. Studies of kinetic properties of the enzyme resulted in variations in active number of Na, K-ATPase molecules as well as its qualitative properties. Sixteen-week-old control male rats showed better affinity to substrate as indicated by 13 % decrease of K m value. The effect persisted also in males subjected to 8 days lasting diabetes; however, in males subjected to 8 weeks lasting diabetes, the effect was lost. In 25-week-old rats, the Na, K-ATPase revealed again altered properties in males and females but the mechanism of the variation was different. In females, the number of active molecules of Na, K-ATPase was higher by 32 % in controls and by 17 % in rats with chronic diabetes when comparing to respective male groups as suggested by increased value of V max. So the properties of Na, K-ATPase in cerebral cortex, playing crucial role in maintaining intracellular homeostasis of Na(+) ions, depend on gender, age, and duration of diabetic insult.
进行了时间序列研究，以表征1型糖尿病对来自正常和链脲佐菌素（STZ）诱导的糖尿病大鼠大脑皮层中钠钾ATP酶特性的影响。在STZ（65mg/kg(-1)）诱导糖尿病8天、8周和16周后的不同时间间隔切除样本。蛋白质免疫印迹分析显示，在糖尿病的所有阶段，雌性和雄性大鼠中钠钾ATP酶α1-3亚型的表达均未发生统计学显著变化。对该酶动力学特性的研究导致钠钾ATP酶分子活性数量及其定性特性发生变化。16周龄的对照雄性大鼠对底物表现出更好的亲和力，Km值降低了13%。这种效应在持续8天糖尿病的雄性大鼠中也持续存在；然而，在持续8周糖尿病的雄性大鼠中，这种效应消失了。在25周龄的大鼠中，钠钾ATP酶在雄性和雌性大鼠中再次表现出特性改变，但变化机制不同。与相应雄性组相比，雌性对照组中钠钾ATP酶活性分子数量增加了32%，慢性糖尿病大鼠中增加了17%，这由Vmax值的增加表明。因此，大脑皮层中的钠钾ATP酶特性在维持细胞内钠离子稳态中起关键作用，它取决于性别、年龄和糖尿病损伤的持续时间。
