胰岛素对兔皮质集合管钾分泌的影响。

Effect of insulin on potassium secretion in rabbit cortical collecting ducts.

作者信息

Furuya H, Tabei K, Muto S, Asano Y

机构信息

Department of Medicine, Jichi Medical School, Tochigi, Japan.

出版信息

Am J Physiol. 1992 Jan;262(1 Pt 2):F30-5. doi: 10.1152/ajprenal.1992.262.1.F30.

DOI:10.1152/ajprenal.1992.262.1.F30

PMID:1733294

Abstract

Insulin is known to play an important role in the regulation of extrarenal K homeostasis. Previous clearance studies have shown that insulin decreases urinary K excretion, but the responsible nephron segments have not been identified. In this microperfusion study, in vitro, the effect of insulin on K transport in the cortical collecting duct (CCD), which is thought to be an important segment for regulation of the final urinary K excretion, was investigated. Basolateral insulin (10(-6) M) significantly inhibited net K secretion by 20% (mean JK = -26.2 +/- 4.2 peq.mm-1.min-1 for controls compared with -21.1 +/- 3.4 with insulin, P less than 0.001) and depolarized the transepithelial voltage (VT, from -14.6 +/- 3.5 to -10.8 +/- 3.5 mV, P less than 0.005), recovery did not occur over 60 min. Insulin (10(-11)-10(-5) M) depressed K secretion and depolarized the VT in a concentration-dependent manner. The half-maximal concentration was 5 x 10(-10) M, which is within the physiological range of plasma insulin concentration. In tubules of deoxycorticosterone acetate-treated rabbits, insulin also produced a significant fall in K secretion (from -43.4 +/- 7.5 to -36.1 +/- 5.7 peq.mm-1.min-1, P less than 0.05). Although luminal Ba (2 mM) decreased K secretion (from -14.4 +/- 2.9 to -7.0 +/- 1.7 peq.mm-1.min-1), basolateral insulin (10(-6) M) inhibited K secretion further (to -4.7 +/- 1.3 peq.mm-1.min-1, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

摘要

已知胰岛素在肾外钾稳态调节中发挥重要作用。以往的清除率研究表明，胰岛素可减少尿钾排泄，但尚未确定负责的肾单位节段。在本微灌注研究中，体外研究了胰岛素对皮质集合管（CCD）钾转运的影响，皮质集合管被认为是调节最终尿钾排泄的重要节段。基底侧胰岛素（10⁻⁶ M）显著抑制净钾分泌20%（对照组平均JK = -26.2 ± 4.2 peq·mm⁻¹·min⁻¹，胰岛素组为-21.1 ± 3.4，P < 0.001），并使跨上皮电压（VT）去极化（从-14.6 ± 3.5 mV降至-10.8 ± 3.5 mV，P < 0.005），60分钟内未恢复。胰岛素（10⁻¹¹ - 10⁻⁵ M）以浓度依赖方式抑制钾分泌并使VT去极化。半数最大浓度为5×10⁻¹⁰ M，处于血浆胰岛素浓度的生理范围内。在醋酸脱氧皮质酮处理的兔肾小管中，胰岛素也使钾分泌显著下降（从-43.4 ± 7.5降至-36.1 ± 5.7 peq·mm⁻¹·min⁻¹，P < 0.05）。尽管管腔钡（2 mM）减少了钾分泌（从-14.4 ± 2.9降至-7.0 ± 1.7 peq·mm⁻¹·min⁻¹），基底侧胰岛素（10⁻⁶ M）进一步抑制钾分泌（至-4.7 ± 1.3 peq·mm⁻¹·min⁻¹，P < 0.01）。（摘要截断于250字）