Sodium-dependent transport of Pi by an established intestinal epithelial cell line (CaCo-2)

Author:

Mohrmann I.,Mohrmann M.,Biber J.,Murer H.

Abstract

The uptake of inorganic phosphate (Pi) was analyzed in monolayers and in apical membrane vesicles (AMV) of the established intestinal cell line CaCo-2. AMV, prepared by a MgCl2 precipitation technique, were enriched approximately 10-fold in alkaline phosphatase activity. Pi uptake into intact cells as well as into AMV was specifically dependent on the presence of sodium. In the presence of high sodium concentrations, the apparent Km for Pi was 214 +/- 17 mumol/l in monolayers and 300 +/- 19.7 mumol/l in AMV. Increasing the sodium concentration increased the apparent affinity of the transport system for Pi but hardly affected the maximal velocity (Vmax). At 0.1 mmol/l Pi and pH 7.4, the apparent Km for sodium was approximately 70 mmol/l in intact cells as well as in AMV. The results obtained in both systems suggested the involvement of two sodium ions and one phosphate ion in the transport process. Advancing confluence--independently of the age of the monolayers--reduced sodium-dependent uptake of Pi significantly by a decrease in Vmax, whereas the apparent Km for Pi remained unchanged. It is concluded that the apical membrane of CaCo-2 cells contains a sodium-dependent transport system for Pi.

Publisher

American Physiological Society

Subject

Physiology (medical),Gastroenterology,Hepatology,Physiology

Cited by 54 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3