Rat colon ornithine and arginine metabolism: Coordinated effects after proliferative stimuli

Xiaoli Han, Michael N. Kazarinoff, Nikolaus Seiler, Bruce A. Stanley

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Ornithine decarboxylase (ODC) catalyzes the first step in the polyamine biosynthetic pathway, a highly regulated pathway in which activity increases during rapid growth. Other enzymes also metabolize ornithine, and in hepatomas, rate of growth correlates with decreased activity of these other enzymes, which thus channels more ornithine to polyamine biosynthesis. Ornithine is produced from arginase cleavage of arginine, which also serves as the precursor for nitric oxide production. To study whether short-term coordination of ornithine and arginine metabolism exists in rat colon, ODC, ornithine aminotransferase (OAT), arginase, ornithine, arginine, and polyamine levels were measured after two stimuli (refeeding and/or deoxycholate exposure) known to synergistically induce ODC activity. Increased ODC activity was accompanied by increased putrescine levels, whereas OAT and arginase activity were reduced by either treatment, accompanied by an increase in both arginine and ornithine levels. These results indicate a rapid reciprocal change in ODC, OAT, and arginase activity in response to refeeding or deoxycholate. The accompanying increases in ornithine and arginine concentration are likely to contribute to increased flux through the polyamine and nitric oxide biosynthetic pathways in vivo.

Original languageEnglish (US)
Pages (from-to)G389-G399
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume280
Issue number3 43-3
DOIs
StatePublished - Mar 2001

All Science Journal Classification (ASJC) codes

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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