Characterization of L-arginine transporters in rat renal inner medullary collecting duct

Feng Wu, Brian Cholewa, David L. Mattson

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)R1506-R1512
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume278
Issue number6 47-6
DOIs
StatePublished - Jun 2000

Keywords

  • Kidney
  • Kidney collecting duct
  • Nitric oxide synthase

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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