AJP - Renal Physiology, Vol 261, Issue 3 420-F426, Copyright © 1991 by American Physiological Society

ARTICLES

Renal brush-border membrane Na(+)-sulfate cotransport: stimulation by thyroid hormone

H. S. Tenenhouse, J. Lee and N. Harvey
Department of Pediatrics, McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada.

The present study was undertaken to examine the interaction of phosphonoformic acid (PFA) with the Na(+)-sulfate cotransporter and the effect of thyroid hormone (triiodothyronine; T3) on Na(+)-dependent sulfate transport and Na(+)-dependent PFA binding in mouse renal brush-border membrane vesicles. PFA inhibits Na(+)-dependent sulfate transport in a competitive manner [apparent inhibitory constant (Ki) = 4.3 +/- 1.1 mM]. T3 administered in pharmacological doses significantly stimulates Na(+)-dependent sulfate transport in renal brush-border membranes compared with vehicle-treated controls. Although T3 has no effect on Na(+)-dependent glucose transport, T3 also stimulates Na(+)-dependent phosphate transport. Kinetic studies demonstrate that T3 increases the apparent maximal velocity (Vmax) for Na(+)-sulfate cotransport without changing the apparent Michaelis constant (Km). T3 does not significantly affect either Na(+)-dependent PFA binding or the phosphate- and sulfate-displaceable components of Na(+)-dependent PFA binding. Finally, Na(+)-dependent brush-border membrane sulfate transport is unchanged in phosphate-deprived mice that exhibit increased Na(+)-phosphate cotransport and in X-linked Hyp mice that exhibit impaired Na(+)-phosphate cotransport. The present results demonstrate that 1) PFA is a competitive inhibitor of Na(+)-sulfate cotransport, 2) T3 stimulates Na(+)-dependent sulfate, as well as Na(+)-dependent phosphate transport, but has no effect on PFA binding, and 3) phosphate deprivation and the X-linked Hyp mutation do not influence Na(+)-sulfate cotransport.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				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]

				H. J. Lee, K. Sagawa, W. Shi, H. Murer, and M. E. Morris Hormonal Regulation of Sodium/Sulfate Co-Transport in Renal Epithelial Cells Experimental Biology and Medicine, October 1, 2000; 225(1): 49 - 57. [Abstract] [Full Text]

				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]

				K. Sagawa, B. Han, D. C. DuBois, H. Murer, R. R. Almon, and M. E. Morris Age- and Growth Hormone-Induced Alterations in Renal Sulfate Transport J. Pharmacol. Exp. Ther., September 1, 1999; 290(3): 1182 - 1187. [Abstract] [Full Text]

				K. Puttaparthi, D. Markovich, N. Halaihel, P. Wilson, H. K. Zajicek, H. Wang, J. Biber, H. Murer, T. Rogers, and M. Levi Metabolic acidosis regulates rat renal Na-Si cotransport activity Am J Physiol Cell Physiol, June 1, 1999; 276(6): C1398 - C1404. [Abstract] [Full Text] [PDF]

				K. Sagawa, H. Murer, and M. E. Morris Effect of experimentally induced hypothyroidism on sulfate renal transport in rats Am J Physiol Renal Physiol, January 1, 1999; 276(1): F164 - F171. [Abstract] [Full Text] [PDF]