2型糖尿病大鼠近球小管Na+,K+-ATPase活性变化

目的 探讨2型糖尿病(type 2 diabetes mellitus, T2DM)近球小管(proximal tubule, PT)的Na ,K -ATPase活性变化.方法 首先建立T2DM大鼠模型,测定血糖、血清胰岛素和内源性洋地黄样物质(endogenous digitalis-like substance, EDLS)水平;微分离大鼠单根PT,液闪法测单根PT的Na ,K -ATPase活性.结果与正常对照组大鼠比较,模型组血糖、血脂、总胆固醇浓度显著升高,胰岛素敏感指数显著下降(P＜0.05,P＜0.01);胰岛素水平不低,PT的Na ,K -ATPase活性均显著升高(P＜0.01);血清EDLS水平显著下降(P＜0.01).大鼠血清EDLS水平与PT的Na ,K -ATPase活性呈显著负相关(r=-0.900, P＜0.01).结论 T2DM大鼠PT的Na ,K -ATPase活性升高,这种酶活性升高与血液中EDLS水平下降有关.

Changes of Na+, K+-ATPase activity in proximal tubules of type 2 diabetic rats

Objective To investigate the changes of Na~ ,K~ -ATPase activity in the proximal tubules (PT) of type 2 diabetes mellitus(T2DM) and the correlation of PT Na~ ,K~ -ATPase activity and endogenous digitalis-like substance (EDLS). Methods Female Wistar rats were developed a rat model of T2DM and then divided into 3 groups after injected stretozotocin, that is, 5 weeks group, 7 weeks group and 9 weeks group. The PT were microdissection by freehand. Na~ ,K~ -ATPase activity of PT were determined by liquid scintillation counter. Serum EDLS and insulin were determined using radioimmunoassay. Results Compared with control group, T2DM rats were associated with hyperglycemia, hypertriglyceridemia, dyslipidemia, and insulin resistance; Na~ ,K~ -ATPase activity of PT in T2DM rats was significantly increased, and there was no significant difference among 3 sub-groups. Serum EDLS level was significantly enhanced in T2DM, however, EDLS levels were no significant difference among 3 sub-groups. Na~ ,K~ -ATPase activity of PT had negative relation with EDLS level in serum. Conclusion Na~ ,K~ -ATPase activity of PT in T2DM rats is increased and EDLS level in serum decrease may play a important role.