| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physiology and Pharmacology, University of Queensland, Brisbane, Queensland 4072, Australia
Heavy metal
intoxication leads to a number of reabsorptive and secretory defects in
renal transport systems. We have studied the effects of several heavy
metals on the expression of the renal Na-Si cotransporter NaSi-1. NaSi-1
cRNA was injected into Xenopus oocytes, and Na-Si cotransport
activity was measured in the presence of mercury, lead, cadmium, or
chromium. Mercury strongly inhibited NaSi-1 transport irreversibly by
reducing both maximal velocity (Vmax) and
Michaelis constant
(Km) for
inorganic sulfate (Si). Lead
inhibited NaSi-1 transport reversibly by decreasing
Vmax but not
Km for
Si. Cadmium showed weak reversible
inhibition of NaSi-1 transport by decreasing only NaSi-1
Vmax. Chromium
strongly inhibited NaSi-1 cotransport reversibly by reducing
Km for
Si by sevenfold, most probably by
binding to the Si site, due to the
strong structural similarity between the
C
and
substrates. In conclusion,
this study presents an initial report demonstrating heavy metals
inhibit renal brush border Na-Si
cotransport via the NaSi-1 protein through various mechanisms and that
this blockade may be responsible for sulfaturia following heavy metal
intoxication.
sodium-sulfate cotransport; brush-border membrane; Xenopus laevis oocytes; nephrotoxicity
This article has been cited by other articles:
|
|
 |
|
  T. Nakada, K. Zandi-Nejad, Y. Kurita, H. Kudo, V. Broumand, C. Y. Kwon, A. Mercado, D. B. Mount, and S. Hirose Roles of Slc13a1 and Slc26a1 sulfate transporters of eel kidney in sulfate homeostasis and osmoregulation in freshwater Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R575 - R585. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. Barbier, G. Jacquillet, M. Tauc, P. Poujeol, and M. Cougnon Acute study of interaction among cadmium, calcium, and zinc transport along the rat nephron in vivo Am J Physiol Renal Physiol, November 1, 2004; 287(5): F1067 - F1075. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. L. Dudas and J. L. Renfro Transepithelial sulfate transport by avian renal proximal tubule epithelium in primary culture Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2002; 283(6): R1354 - R1361. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Markovich Physiological Roles and Regulation of Mammalian Sulfate Transporters Physiol Rev, October 1, 2001; 81(4): 1499 - 1533. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Mercado, P. de los Heros, N. Vazquez, P. Meade, D. B. Mount, and G. Gamba Functional and molecular characterization of the K-Cl cotransporter of Xenopus laevis oocytes Am J Physiol Cell Physiol, August 1, 2001; 281(2): C670 - C680. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Sagawa, I. M. Darling, H. Murer, and M. E. Morris Glucocorticoid-Induced Alterations of Renal Sulfate Transport J. Pharmacol. Exp. Ther., August 1, 2000; 294(2): 658 - 663. [Abstract] [Full Text]
|
|
|
|
 |
|
 L. Beck and D. Markovich The Mouse Na+-Sulfate Cotransporter Gene Nas1. CLONING, TISSUE DISTRIBUTION, GENE STRUCTURE, CHROMOSOMAL ASSIGNMENT, AND TRANSCRIPTIONAL REGULATION BY VITAMIN D J. Biol. Chem., April 14, 2000; 275(16): 11880 - 11890. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Vazquez, A. Monroy, E. Dorantes, R. A. Munoz-Clares, and G. Gamba Functional differences between flounder and rat thiazide-sensitive Na-Cl cotransporter Am J Physiol Renal Physiol, April 1, 2002; 282(4): F599 - F607. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
