Two-dimensional high-performance liquid chromatographic determination of day-night variation of d-alanine in mammals and factors controlling the circadian changes Amino Acid Analysis

Sachise Karakawa, Yurika Miyoshi, Ryuichi Konno, Satoru Koyanagi, Masashi Mita, Shigehiro Ohdo, Kenji Hamase

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

d-Alanine (d-Ala) is one of the naturally occurring d-amino acids in mammals, and its amount is known to have characteristic circadian changes. It is a candidate for a novel physiologically active substance and/or a biomarker, and the regulation mechanisms of the intrinsic amounts of d-Ala are expected to be clarified. In the present study, the effects of the possible factors controlling the d-Ala amounts, e.g., diet, d-amino acid oxidase (DAO) and intestinal bacteria, on the day-night changes in the intrinsic d-Ala amounts have been investigated using a highly sensitive and selective two-dimensional high-performance liquid chromatographic system combining a reversed-phase column and an enantioselective column. The circadian rhythm was not changed under fasting conditions. In the mice lacking d-amino acid oxidase activity (ddY/DAO- mice), clear day-night changes were still observed, suggesting that the factors controlling the d-Ala rhythm were not their food and DAO activity. On the other hand, in the germ-free mice, quite low amounts of d-Ala were detected compared with those in the control mice, indicating that the main origin of d-Ala in the mice is intestinal bacteria. Because the d-Ala amounts in the digesta containing intestinal bacteria did not show the day-night changes, the controlling factor of the circadian changes of the d-Ala amount was suggested to be the intestinal absorption.

Original languageEnglish
Pages (from-to)8083-8091
Number of pages9
JournalAnalytical and Bioanalytical Chemistry
Volume405
Issue number25
DOIs
Publication statusPublished - Oct 1 2013

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry

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