Umeda F, Noda K, Hashimoto T, Yamashita T, Nawata H
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Diabetes Res. 1989 Nov;12(3):125-9.
The binding capacity of ouabain to erythrocyte Na,K-ATPase was determined to analyze alterations in this enzyme activity in non-insulin-dependent diabetic patients. A significant (p less than 0.001) reduction of the binding capacity of ouabain was found in erythrocytes obtained from the diabetic patients with polyneuropathy (0.51 +/- 0.02 pmol/10(9) erythrocytes, m +/- SE, n = 14) as compared with the patients without neuropathy (0.67 +/- 0.02, n = 14) or age-matched control subjects (0.71 +/- 0.04, n = 11). Accordingly, the effect of an aldose reductase inhibitor (ARI; Ponalrestat) on erythrocyte Na,K-ATPase activity was studied following two or three months oral administration in seven of the diabetic patients with polyneuropathy. After treatment with Ponalrestat the mean binding capacity of ouabain was significantly increased from 0.53 +/- 0.04 to 0.57 +/- 0.03 (p less than 0.05 by paired t-test). Furthermore, enzyme kinetics showed that in normal subjects the apparent Km and Vmax of erythrocyte membrane Na,K-ATPase were 0.51 +/- 0.07 mM (n = 5, m +/- SE) and 7.19 +/- 0.27 nmol Pi/mg protein/min (n = 5, m +/- SE), respectively. The Vmax with 3 mM ATP was significantly (p less than 0.05) decreased in the diabetic patients with polyneuropathy as compared with age-matched control subjects. However, the apparent Km did not change. Finally, the in vitro effect of Ponalrestat was examined in erythrocyte membrane fractions from the diabetic patients with polyneuropathy. The activity of erythrocyte membrane Na,K-ATPase was found to be directly stimulated about 1.2 fold by the addition of pharmacological doses of Ponalrestat (10(-10), 10(-8), 10(-6) M).(ABSTRACT TRUNCATED AT 250 WORDS)
测定哇巴因与红细胞钠钾 - ATP酶的结合能力，以分析非胰岛素依赖型糖尿病患者该酶活性的变化。与无神经病变的患者（0.67±0.02，n = 14）或年龄匹配的对照受试者（0.71±0.04，n = 11）相比，在患有多发性神经病变的糖尿病患者的红细胞中发现哇巴因的结合能力显著降低（p＜0.001）（0.51±0.02 pmol/10⁹红细胞，m±SE，n = 14）。因此，对7例患有多发性神经病变的糖尿病患者进行了两到三个月的口服给药后，研究了醛糖还原酶抑制剂（ARI；波那司他）对红细胞钠钾 - ATP酶活性的影响。用波那司他治疗后，哇巴因的平均结合能力从0.53±0.04显著增加到0.57±0.03（配对t检验，p＜0.05）。此外，酶动力学表明，在正常受试者中，红细胞膜钠钾 - ATP酶的表观Km和Vmax分别为0.51±0.07 mM（n = 5，m±SE）和7.19±0.27 nmol Pi/mg蛋白质/分钟（n = 5，m±SE）。与年龄匹配的对照受试者相比，患有多发性神经病变的糖尿病患者中3 mM ATP时的Vmax显著降低（p＜0.05）。然而，表观Km没有变化。最后，在患有多发性神经病变的糖尿病患者的红细胞膜组分中检测了波那司他的体外作用。发现加入药理剂量的波那司他（10⁻¹⁰、10⁻⁸、10⁻⁶ M）可使红细胞膜钠钾 - ATP酶的活性直接提高约1.2倍。（摘要截短于250字）
