Morikawa Akiko, Hamase Kenji, Miyoshi Yurika, Koyanagi Satoru, Ohdo Shigehiro, Zaitsu Kiiyoshi
Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
J Chromatogr B Analyt Technol Biomed Life Sci. 2008 Nov 1;875(1):168-73. doi: 10.1016/j.jchromb.2008.04.004.
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.
在具有昼夜和夜行习性的大鼠中，研究了哺乳动物体内固有D-氨基酸D-丙氨酸（D-Ala）的昼夜变化，并将其变化曲线与L-丙氨酸、其他D-氨基酸和几种激素的变化曲线进行了比较。使用一种灵敏且具选择性的二维高效液相色谱系统，该系统结合了微ODS柱和对映体选择性柱，在与4-氟-7-硝基-2,1,3-苯并二唑（NBD-F）进行荧光衍生化后，测定大鼠血浆、胰腺和垂体前叶中的D-Ala。在具有昼夜和夜行习性的大鼠中，D-Ala的量在睡眠期较高，而在活动期较低，这首次表明D-Ala与动物的活动节律密切相关。相比之下，L-丙氨酸和其他D-氨基酸未表现出任何明显的昼夜变化。在具有昼夜和夜行习性的大鼠中，D-Ala的昼夜变化与血浆胰岛素水平的变化呈负相关。结合我们之前的研究结果，即D-Ala定位于大鼠胰腺中分泌胰岛素的β细胞，强烈提示D-Ala在哺乳动物中与胰岛素存在某些功能关系。
