Characterization of L-arginine transporters in rat renal inner medullary collecting duct. Am J Physiol Regul Integr Comp Physiol 2000 Jun;278(6):R1506-12
Date
06/10/2000Pubmed ID
10848517DOI
10.1152/ajpregu.2000.278.6.R1506Scopus ID
2-s2.0-0033946125 (requires institutional sign-in at Scopus site) 44 CitationsAbstract
Previous work from our laboratory has demonstrated that the inner medullary collecting duct (IMCD) expresses a large amount of nitric oxide synthase (NOS) activity. The present study was designed to characterize the transport of NOS substrate, L-arginine, in a suspension of bulk-isolated IMCD cells from the Sprague-Dawley rat kidney. Biochemical transport studies demonstrated an L-arginine transport system in IMCD cells that was saturable and Na(+) independent (n = 6). L-Arginine uptake by IMCD cells was inhibited by the cationic amino acids L-lysine, L-homoarginine, and L-ornithine (10 mmol/l each) and unaffected by the neutral amino acids L-leucine, L-serine, and L-glutamine. Both L-ornithine (n = 6) and L-lysine (n = 6) inhibited NOS enzymatic activity in a dose-dependent manner in IMCD cells, supporting the important role of L-arginine transport for NO production by this tubular segment. Furthermore, RT-PCR of microdissected IMCD confirmed the presence of cationic amino acid transporter CAT1 mRNA, whereas CAT2A, CAT2B, and CAT3 were not detected. These results indicate that L-arginine uptake by IMCD cells occurs via system y(+), is encoded by CAT1, and may participate in the regulation of NO production in this renal segment.
Author List
Wu F, Cholewa B, Mattson DLMESH terms used to index this publication - Major topics in bold
Amino Acid Transport SystemsAnimals
Arginine
Biological Transport
Carrier Proteins
Cations
Citrulline
Enzyme Inhibitors
Gene Expression
Homeostasis
Kidney Medulla
Kidney Tubules, Collecting
Lysine
Male
NG-Nitroarginine Methyl Ester
Nitric Oxide Synthase
Ornithine
RNA, Messenger
Rats
Rats, Sprague-Dawley
Substrate Specificity
Tritium
Water-Electrolyte Balance
beta-Alanine
omega-N-Methylarginine
