大鼠胰岛中的 D-丙氨酸。
D-Alanine in the islets of Langerhans of rat pancreas.
机构信息
Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, IL 61801, USA.
Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, IL 61801, USA.
出版信息
Biochem Biophys Res Commun. 2014 May 2;447(2):328-33. doi: 10.1016/j.bbrc.2014.03.153. Epub 2014 Apr 8.
Relatively high levels of D-alanine (D-Ala), an endogenous D-amino acid, have been found in the endocrine systems of several animals, especially in the anterior pituitary; however, its functional importance remains largely unknown. We observed D-Ala in islets of Langerhans isolated from rat pancreas in significantly higher levels than in the anterior/intermediate pituitary; specifically, 180±60 fmol D-Ala per islet (300±100 nmol/gislet), and 10±2.5 nmol/g of wet tissue in pituitary. Additionally, 12±5% of the free Ala in the islets was in the d form, almost an order of magnitude higher than the percentage of D-Ala found in the pituitary. Surprisingly, glucose stimulation of the islets resulted in D-Ala release of 0.6±0.5 fmol per islet. As D-Ala is stored in islets and released in response to changes in extracellular glucose, D-Ala may have a hormonal role.
相对较高水平的 D-丙氨酸（D-Ala），一种内源性 D-氨基酸，已在几种动物的内分泌系统中被发现，尤其是在前垂体中；然而，其功能意义在很大程度上仍然未知。我们观察到从大鼠胰腺分离的胰岛中 D-Ala 的含量明显高于前/中间垂体；具体而言，每个胰岛中有 180±60 飞摩尔 D-Ala（300±100 nmol/胰岛），而在垂体中的湿组织中为 10±2.5 nmol/g。此外，胰岛中游离 Ala 的 12±5%呈 d 型，几乎比在垂体中发现的 D-Ala 百分比高一个数量级。令人惊讶的是，葡萄糖刺激胰岛导致每个胰岛释放 0.6±0.5 飞摩尔的 D-Ala。由于 D-Ala 储存在胰岛中并响应细胞外葡萄糖的变化而释放，D-Ala 可能具有激素作用。
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