AJP - Renal Physiology, Vol 257, Issue 6 974-F977, Copyright © 1989 by American Physiological Society

ARTICLES

Early adaptation of renal magnesium reabsorption in response to magnesium restriction

I. M. Shafik and G. A. Quamme
Department of Medicine, University Hospital, University of British Columbia, Vancouver, Canada.

Dietary magnesium restriction with hypomagnesia is normally associated with diminished urinary magnesium excretion. Young rats were pair fed control magnesium diets (0.05% MgSO4) and magnesium-restricted diets (less than 0.01% Mg), and tubular magnesium reabsorption was assessed to determine the importance of filtered load (plasma magnesium) and to establish the presence of cellular adaptation of magnesium transport. Urinary magnesium excretion decreased from 17.2 +/- 2.7 to 5.9 +/- 1.2% over 20 h on low-magnesium diets without a change in plasma concentration (0.61 +/- 0.02 mM). This cellular adaptation was rapid (within 5 h), specific (without effect on sodium and calcium), and sensitive (without change in plasma concentration). Micropuncture studies demonstrated that cellular adaptation occurred within the loop of Henle. After 20 h, plasma magnesium fell with an associated further decrease in fractional magnesium excretion. Accordingly, cellular adaptation of magnesium transport occurs with magnesium-deficient diets, and alterations in filtered magnesium and plasma magnesium concentration are not necessary for magnesium conservation.

This article has been cited by other articles:

				A. Goytain, R. M. Hines, and G. A. Quamme Functional characterization of NIPA2, a selective Mg2+ transporter Am J Physiol Cell Physiol, October 1, 2008; 295(4): C944 - C953. [Abstract] [Full Text] [PDF]

				L. J. Rondon, W. M. T. Groenestege, Y. Rayssiguier, and A. Mazur Relationship between low magnesium status and TRPM6 expression in the kidney and large intestine Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2008; 294(6): R2001 - R2007. [Abstract] [Full Text] [PDF]

				A. Goytain and G. A. Quamme Identification and characterization of a novel family of membrane magnesium transporters, MMgT1 and MMgT2 Am J Physiol Cell Physiol, February 1, 2008; 294(2): C495 - C502. [Abstract] [Full Text] [PDF]

				E. Efrati, J. Arsentiev-Rozenfeld, and I. Zelikovic The human paracellin-1 gene (hPCLN-1): renal epithelial cell-specific expression and regulation Am J Physiol Renal Physiol, February 1, 2005; 288(2): F272 - F283. [Abstract] [Full Text] [PDF]

				L.-J. Dai, G. Ritchie, D. Kerstan, H. S. Kang, D. E. C. Cole, and G. A. Quamme Magnesium Transport in the Renal Distal Convoluted Tubule Physiol Rev, January 1, 2001; 81(1): 51 - 84. [Abstract] [Full Text] [PDF]

				D. Keenan, A. Romani, and A. Scarpa Differential Regulation of Circulating Mg2+ in the Rat by ß1- and ß2-Adrenergic Receptor Stimulation Circ. Res., November 1, 1995; 77(5): 973 - 983. [Abstract] [Full Text]