title: Circadian changes of D-alanine and related compounds in rats and the effect of restricted feeding on their amounts.
abstract: The circadian changes of D-alanine (D-Ala), an intrinsic D-amino acid found in mammals, were investigated in rats with diurnal and nocturnal habits, and the profiles were compared to those of L-Ala, other D-amino acids and several hormones. Determination of D-Ala in the rat plasma, pancreas and anterior pituitary gland was carried out using a sensitive and selective two-dimensional HPLC system combining a micro-ODS column and an enantioselective column after fluorescence derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). The amount of D-Ala was high during the sleeping period and low during the active period in rats with both diurnal and nocturnal habits, indicating for the first time that the D-Ala is closely related to the activity rhythm of animals. In contrast, L-Ala and other D-amino acids did not show any clear circadian changes. The circadian change of D-Ala inversely correlated with that of the plasma insulin level in rats with both diurnal and nocturnal habits. Considered together with our previous findings that D-Ala is localized in the insulin secreting beta-cells in the rat pancreas, it is strongly suggested that D-Ala has some functional relationships to insulin in mammals.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Morikawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Hamase
authors.forename: Yurika
authors.initials: Y
authors.lastname: Miyoshi
authors.forename: Satoru
authors.initials: S
authors.lastname: Koyanagi
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Ohdo
authors.forename: Kiiyoshi
authors.initials: K
authors.lastname: Zaitsu
mesh_terms: D000409:Alanine / Q000378:metabolism*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002940:Circadian Rhythm / Q000502:physiology*; D003345:Corticosterone / Q000378:metabolism; D005247:Feeding Behavior / Q000502:physiology*; D007328:Insulin / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D007328:Insulin; D001224:Aspartic Acid; D012694:Serine; D008550:Melatonin; D000409:Alanine; D003345:Corticosterone