d-Aspartate, d-serine and d-alanine are a regular occurrence in mammalian endocrine tissues, though in amounts varying with the type of gland. The pituitary gland, pineal gland, thyroid, adrenal glands and testis contain relatively large amounts of d-aspartate in all species examined. d-alanine is relatively abundant in the pituitary gland and pancreas. High levels of d-serine characterize the hypothalamus. d-leucine, d-proline and d-glutamate are generally low. The current knowledge of physiological roles of d-amino acids in endocrine tissues is far from exhaustive, yet the topic is attracting increasing interest because of its potential in pharmacological application. d-aspartate is known to act at all levels of the hypothalamus–pituitary–testis axis, playing a key role in reproductive biology in several vertebrate classes. An involvement of d-amino acids in the endocrine function of the pancreas is emerging. d-Aspartate has been immunolocalized in insulin-containing secretory granules in INS-1 E clonal β cells and is co-secreted with insulin by exocytosis. Specific immunolocalization of d-alanine in pituitary ACTH-secreting cells and pancreatic β-cells suggests that this amino acid participates in blood glucose regulation in mammals. By modulating insulin secretion, d-serine probably participates in the control of systemic glucose metabolism by modulating insulin secretion. We anticipate that future investigation will significantly increase the functional repertoire of d-amino acids in homeostatic control.

d-天门冬氨酸，d-丝氨酸和d-丙氨酸在哺乳动物内分泌组织中经常出现，尽管其数量随腺体的类型而变化。在所有检查的物种中，垂体，松果体，甲状腺，肾上腺和睾丸均含有相对大量的d-天冬氨酸。d-丙氨酸在垂体和胰腺中相对丰富。高水平的d-丝氨酸是下丘脑的特征。d-亮氨酸，d-脯氨酸和d-谷氨酸通常较低。d的生理作用的当前知识内分泌组织中的氨基酸远非穷尽，但是由于其在药理学应用中的潜力，该话题引起了越来越多的兴趣。已知d-天门冬氨酸在下丘脑-垂体-睾丸轴的所有水平上起作用，在几个脊椎动物类别的生殖生物学中起着关键作用。d-氨基酸参与了胰腺的内分泌功能。d-天冬氨酸已被免疫定位在INS-1 E克隆β细胞的含胰岛素的分泌颗粒中，并通过胞吐作用与胰岛素共同分泌。d的特异性免疫定位垂体ACTH分泌细胞和胰腺β细胞中的-丙氨酸表明该氨基酸参与哺乳动物的血糖调节。通过调节胰岛素分泌，d-丝氨酸可能通过调节胰岛素分泌参与系统性葡萄糖代谢的控制。我们预计，未来的研究将大大增加d-氨基酸在稳态控制中的功能。