Molecular basis of osmotic regulation

Author:

Burg M. B.1

Affiliation:

1. National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892–1598, USA.

Abstract

Cells almost universally respond to the stress of long-term hyperosmolality by accumulating compatible organic osmolytes. This allows them to maintain normal cell volume without a deleterious increase in intracellular inorganic ion concentration. Cells in the renal inner medulla are exposed to variable concentrations of salt and urea that may reach molal levels. The organic osmolytes that they accumulate include sorbitol, betaine, inositol, taurine, and glycerophosphocholine (GPC). This review considers recent advances in understanding osmotic regulation of these substances. Sorbitol is synthesized from glucose catalyzed by aldose reductase. Hypertonicity elevates the abundance of this enzyme by increasing transcription of its gene. Betaine is taken up via a specialized transporter. Hypertonicity raises the number of transporters by increasing their transcription. Current studies demonstrate that the 5' regions flanking the aldose reductase and betaine transporter genes contain osmotic response elements that increase transcription in response to hypertonicity. Osmotic regulation of inositol and taurine uptake also involves increased expression of specific transporter genes. GPC is unique in that its level rises in response to high urea, as well as hypertonicity. GPC accumulation is mainly regulated by changes in its degradation to choline, catalyzed by GPC:choline phosphodiesterase. Numerous other genes, including those for heat shock proteins, are also induced by hypertonicity. Their regulation and their role in osmotic regulation are the subject of considerable ongoing research.

Publisher

American Physiological Society

Subject

Physiology

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