Acute hypoxia increases intracellular L-arginine content in cultured porcine pulmonary artery enclothelial cells

Yunchao Su, Edward R. Block

Research output: Contribution to journalArticle

13 Scopus citations


Exposure to hypoxia (0% O2) for 4-24 h resulted in increased intracellular L-arginine content and increased activity of calpain, a calcium-dependent neutral cysteine protease, in pulmonary artery endothelial cells. Calpain-inhibitor I abolished the increased L-arginine content in hypoxic cells. When endothelial cell proteins were labeled with [3H]-L-arginine and the cells exposed to hypoxia, we observed an increase in free [3H]-L-arginine and a decrease in [3H]-L-arginine-labeled proteins. Once again, calpain-inhibitor I prevented the increases in free [3H]-L-arginine and the decreases in [3H]-L-arginine-labeled proteins in hypoxic cells. Hypoxia also inhibited the synthesis of L-arginine-containing proteins. Thus, the increase in intracellular L-arginine content in hypoxic pulmonary artery endothelial cells is caused by an increase in proteolysis secondary to calpain and a decrease in protein synthesis. These results indicate that hypoxia can modulate the availability of free intracellular L-arginine, the exclusive precursor of nitric oxide (NO) and the primary substrate of NO synthase, by affecting the synthesis and degradation of cellular proteins.

Original languageEnglish (US)
Pages (from-to)349-353
Number of pages5
JournalJournal of Cellular Physiology
Issue number2
Publication statusPublished - May 1996
Externally publishedYes


ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Cell Biology

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