Quantification of nitric oxide synthase activity in microdissected segments of the rat kidney

Feng Wu, Frank Park, Allen W. Cowley, David L. Mattson

Research output: Contribution to journalArticlepeer-review

173 Scopus citations


This study was designed to quantify nitric oxide synthase (NOS) activity in microdissected glomeruli (Glm), pars convoluta, pars recta, cortical collecting duct, cortical thick ascending limb, outer medullary collecting duct, medullary thick ascending limb and thin limb, inner medullary collecting duct (IMCD) and thin limb, and vasa recta (VR). Total protein from microdissected segments was incubated with L-[3H]arginine and appropriate cofactors, and the L-arginine and converted L-citrulline were separated by reverse-phase HPLC and radiochemically quantitated. NOS activity was found to be greatest in IMCD (11.5 ± 1.0 fmol citrulline · mm-1 · h-1) and moderate in Glm (1.9 ± 0.3 fmol · glomerulus-1 · h-1) and VR (3.2 ± 0.8 fmol · mm-1 · h-1). All other renal structures studied exhibited significantly less NOS activity. The mRNA for NOS isoforms in the NOS activity-positive segments was then identified by RT-PCR. The IMCD contained mRNA for neuronal (nNOS), endothelial (eNOS), and inducible NOS (iNOS), but Glm and VR only expressed the mRNA for nNOS and eNOS. These experiments demonstrate that the greatest enzymatic activity for NO production in the kidney is in the IMCD, three- to sixfold less activity is present in the Glm and VR, and minimal NOS activity is found in other segments studied.

Original languageEnglish (US)
Pages (from-to)F874-F881
JournalAmerican Journal of Physiology - Renal Physiology
Issue number6 45-6
StatePublished - Jun 1996
Externally publishedYes


  • High-pressure liquid chromatography
  • Kidney tubules
  • Messenger ribonucleic acid
  • Sprague-Dawley rat

ASJC Scopus subject areas

  • Physiology
  • Urology


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