IMR Press / FBL / Volume 5 / Issue 3 / DOI: 10.2741/beyenbach

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
Renal handling of magnesium in fish: from whole animal to brush border membrane vesicles
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1 Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
Academic Editor:Hector Rasgado-Flores
Front. Biosci. (Landmark Ed) 2000, 5(3), 712–719;
Published: 1 August 2000
(This article belongs to the Special Issue Magnesium and cell proliferation and differentiation)

Of all known vertebrate tissues, the kidneys of fish are the champions of Mg transport. They can switch from Mg conservation in fresh water to Mg wasting in seawater. High rates of tubular transport and the ability to alternate between Mg reabsorption and secretion make fish kidneys the model of choice investigating the mechanisms of transepithelial and membrane Mg transport and its regulation by extracellular hormones and intracellular messengers. Studies in isolated proximal tubules indicate active transepithelial Mg transport that requires metabolic energy for both tubular reabsorption and secretion. Whether active transport is primary and mediated by a Mg-pump, or secondary and mediated via cotransport or antiport, is unknown. In fresh water fish, the active transport pathway appears to include a Mg-channel located in brush-border membranes of proximal tubules. Although plasma Mg concentrations are well protected, a primary hormone controlling Mg balance has yet to be identified in any animal. Moreover, the mechanisms of intracellular Mg homeostasis, especially in epithelial cells with high Mg throughput, are unknown. New methods, including Mg imaging and genetic/molecular approaches promise to unravel Mg transport mechanisms in teleost renal tubules.

Magnesium Transport
Proximal Renal Tubule
Collecting Duct
Tubular Secretion
Tubular Reabsorption
Osmotic And Ionic Regulation
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