ENDOGENOUS SODIUM-PUMP INHIBITORS IN HUMAN URINE - FURTHER IDENTIFICATION OF INHIBITORS OF NA-K-ATPASE

被引：8
作者：
KRAMER, HJ
KRAMPITZ, G
BACKER, A
MICHEL, H
KRAMPITZ, G
MEYERLEHNERT, H
机构：
[1] Medical Policlinic, Department of Medicine, University of Bonn, Bonn
[2] Division of Biochemistry, University of Bonn, Bonn
[3] Institute of Anatomy and Physiology, University of Bonn, Bonn
来源：
AMERICAN JOURNAL OF HYPERTENSION | 1995年 / 8卷 / 07期
关键词：
SODIUM PUMP INHIBITORS; HUMAN; URINE; OUABAIN-LIKE FACTORS; ASCORBIC ACID DERIVATIVES;
D O I：
10.1016/0895-7061(95)00125-9
中图分类号：
R6 [外科学];
学科分类号：
1002 ; 100210 ;
摘要：
We investigated the presence of endogenous Na-K-ATPase inhibitor(s), ie, ouabain-like factors (OLFs), in the urine of salt-loaded healthy subjects. For this purpose 24-h urine was collected on days 3, 4, and 5 of high sodium intake (>30 g NaCl/day). The samples then were lyophilized. Redissolved urine concentrates were acidified (pH 3.5) and subjected to gelchromatography on a Sephadex G-25 column where the OLFs eluted in the post-salt fraction IV. When lyophilized fraction IV was rechromatographed on Sephadex G-10, OLFs with molecular mass (M(r)) of approximately 400 eluted in a late fraction IV/8 separate from added ouabain, ouabagenin (or digoxin), which eluted shortly after void volume. With the subsequent reverse-phase HPLC of fraction IV/8 a polar OLF-1 eluted in fraction IV/8a after the void volume in the water phase and a more apolar OLF-2 eluted at 20% acetonitrile in fraction IV/8d. Only the more apolar OLF-2 cross-reacted with a digoxin antibody. By preparative thin-layer chromatography OLF-1 and OLF-2 were purified as single compounds with potent dose-dependent Na-K-ATPase inhibition and K-i-values approximating 1.5 x 10(-5) mol/L and 1.5 x 10(-4) mol/L, respectively. Mass-spectroscopy (MS) showed M(r) of 391 and H-1-NMR characterized the endogenous urinary apolar OLF-2 as a compound that is structurally totally unrelated to ouabain; infrared (IR) spectroscopy of OLF-1 and OLF-2 also revealed no similarity with ouabain. In contrast, data from MS, NMR-, and IR-spectroscopy show structural resemblance with ascorbic acid derivatives, some of these having strong inhibitory effects on Na-K-ATPase.
引用
收藏
页码：753 / 760
页数：8
相关论文
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