TY - JOUR
T1 - 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
AU - Karakawa, Sachise
AU - Miyoshi, Yurika
AU - Konno, Ryuichi
AU - Koyanagi, Satoru
AU - Mita, Masashi
AU - Ohdo, Shigehiro
AU - Hamase, Kenji
N1 - Funding Information:
Acknowledgments This work was supported in part by a Grant-in-Aid for Scientific Research from Japan Society for the Promotion of Science.
PY - 2013/10
Y1 - 2013/10
N2 - 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.
AB - 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.
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U2 - 10.1007/s00216-013-7071-2
DO - 10.1007/s00216-013-7071-2
M3 - Article
C2 - 23732868
AN - SCOPUS:84885293204
VL - 405
SP - 8083
EP - 8091
JO - Fresenius Zeitschrift fur Analytische Chemie
JF - Fresenius Zeitschrift fur Analytische Chemie
SN - 0016-1152
IS - 25
ER -