Faculty Collaboration Database

Influence of dietary NaCl on L-arginine transport in the renal medulla. Am J Physiol Regul Integr Comp Physiol 2004 Jan;286(1):R89-93

Date

09/27/2003

Pubmed ID

14512271

DOI

10.1152/ajpregu.00309.2003

Scopus ID

2-s2.0-0346727468 (requires institutional sign-in at Scopus site)   15 Citations

Abstract

Previous work demonstrated that l-arginine, the substrate for nitric oxide (NO) synthase, is carried into inner medullary collecting duct (IMCD) cells via system y+, that the major system y+ gene product in IMCD is the cationic amino acid transporter 1 (CAT1), and that blockade of l-arginine uptake in the renal medulla decreases NO and leads to systemic hypertension. The present study determined the influence of dietary sodium intake on l-arginine uptake in IMCD, on CAT1 immunoreactive protein in the renal medulla, and on the hypertensive response to blockade of l-arginine uptake in the renal medulla. Transport studies in bulk-isolated IMCD demonstrated that l-arginine uptake by IMCD was significantly greater (663 +/- 100 pmol x mg(-1) x min(-1), n = 6) in rats exposed to a low-sodium diet (0.4% NaCl) compared with rats on a normal (1% NaCl, 519 +/- 78 pmol x mg(-1) x min(-1), n = 6) or high-sodium diet (4.0% NaCl, 302 +/- 27 pmol x mg(-1) x min(-1), n = 6). Immunoblotting experiments demonstrated that CAT1 immunoreactive protein was significantly decreased by approximately 30% in rats maintained on a high-NaCl diet (n = 5) compared with rats on a low-NaCl diet (n = 5). In contrast to the l-arginine transport and immunoblotting data, in vivo blockade of l-arginine uptake led to hypertension of equal magnitude in rats maintained on a low- or high-NaCl diet. These results indicate that sodium loading leads to a decrease in immunoreactive CAT1 protein in the rat renal medulla, resulting in decreased l-arginine uptake capacity. The decrease in l-arginine uptake capacity, however, does not alter the blood pressure response to l-arginine uptake inhibition in the renal medulla.

Author List

Zewde T, Wu F, Mattson DL

MESH terms used to index this publication - Major topics in bold

Animals
Arginine
Biological Transport
Blood Pressure
Cationic Amino Acid Transporter 1
Diet
Dose-Response Relationship, Drug
Kidney Medulla
Lysine
Male
Ornithine
Rats
Rats, Sprague-Dawley
Sodium Chloride