title: Circadian variations in the liver metabolites of medaka (Oryzias latipes).
abstract: Circadian rhythms are biological rhythms with a period of around 24 hours. In this study, we compared the metabolome of the liver of medaka during the day and night. To comprehensively analyze the circadian variations in the levels of metabolites in the liver, livers were isolated from Zeitgeber time (ZT)4 and ZT16, and the variations in metabolite levels were evaluated. Inosinemonophosphate (IMP) and uridinemonophosphate (UMP) were found to be increased at night, indicating that nucleotide synthesis is most active during the night. Furthermore, the levels of metabolites of the tricarboxylic acid cycle were also reduced at night. In addition, the levels of many amino acids were reduced during the night, suggesting that the amino acids had been degraded. Moreover, the citrulline/ornithine ratio, which is related to arginine consumption, was lower during the day than at night. This pattern suggests that the urea cycle is activated during the day, whereas large amounts of nitric oxide and citrulline may be produced from arginine via nitric oxide synthase during the night. The results of this metabolomic analysis may be useful in future fundamental research to provide insight into chronobiology as well as applied research on drug evaluations using medaka as a model species.
authors: Center for Regenerative Medicine, Yamaguchi University School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.|Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.
authors: Koichi
authors: K
authors: Fujisawa
authors: Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.
authors: Taro
authors: T
authors: Takami
authors: Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.
authors: Yoshitaka
authors: Y
authors: Kimoto
authors: Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.
authors: Toshihiko
authors: T
authors: Matsumoto
authors: Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.
authors: Naoki
authors: N
authors: Yamamoto
authors: Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachidori, Chuo-Ku, Niigata 951-8510, Japan.
authors: Shuji
authors: S
authors: Terai
authors: Center for Regenerative Medicine, Yamaguchi University School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.|Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Minami Kogushi 1-1-1, Ube Yamaguchi 755-8505, Japan.
authors: Isao
authors: I
authors: Sakaida
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D016000:Cluster Analysis; D004734:Energy Metabolism; D008099:Liver / Q000378:metabolism*; D008124:Locomotion / Q000235:genetics; D053858:Metabolic Networks and Pathways; D055442:Metabolome; D055432:Metabolomics / Q000379:methods; D009043:Motor Activity / Q000235:genetics; D009990:Oryzias / Q000502:physiology*