Tryptophan loading increases daytime serum melatonin levels in intact and pinealectomized rats

Ken Yaga, Russel J. Reiter, Bruce A. Richardson

Research output: Contribution to journalArticle

66 Scopus citations

Abstract

L-tryptophan (L-Trp) effects on serum and pineal melatonin were studied in fasted and non-fasted rats. Oral administration of L-Trp during the day caused serum melatonin to increase 4-fold compared to that of saline treated rats; this occurred in both fasted and non-fasted animals. In the same animals, neither NAT, HIOMT, not melatonin levels were changed. In a second study, pinealectomized rats were loaded with L-Trp. In these animals, as in those that had an intact pineal gland, L-Trp loading caused a large increase in immunoreactive serum melatonin. The results suggest that the increased melatonin in serum due to L-Trp administration is primarily derived from an extrapineal organ.

Original languageEnglish (US)
Pages (from-to)1231-1238
Number of pages8
JournalLife Sciences
Volume52
Issue number14
DOIs
StatePublished - 1993

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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