Stojilkovic Stanko S, Zemkova Hana
Section on Cellular Signaling, Program in Developmental Neuroscience, The Eunice Kennedy Shiver National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-4510.
Wiley Interdiscip Rev Membr Transp Signal. 2013;2(4):173-180. doi: 10.1002/wmts.89.
The endocrine system is the system of ductless glands and single cells that synthetize hormones and release them directly into the bloodstream. Regulation of endocrine system is very complex and ATP and its degradable products ADP and adenosine contribute to its regulation acting as extracellular messengers for purinergic receptors. These include P2X receptors, a family of ligand-gated ion channels which expression and roles in endocrine tissues are reviewed here. There are seven mammalian purinergic receptor subunits, denoted P2X1 through P2X7, and the majority of these subunits are also expressed in secretory and non-secretory cells of endocrine system. Functional channels have been identified in the neuroendocrine hypothalamus, the posterior and anterior pituitary, the thyroid gland, the adrenals, the endocrine pancreas, the gonads and the placenta. Native channels are capable of promoting calcium influx through its pore in both excitable and non-excitable cells, as well as of increasing electrical activity in excitable cells by membrane depolarization. This leads to generation of calcium transients and stimulation of hormone release. The pattern of expression and action of P2XRs in endocrine system suggests that locally produced ATP amplifies and synchronizes the secretory responses of individual cells.
内分泌系统是由无导管腺体和单个细胞组成的系统，这些腺体和细胞合成激素并将其直接释放到血液中。内分泌系统的调节非常复杂，三磷酸腺苷（ATP）及其可降解产物二磷酸腺苷（ADP）和腺苷作为嘌呤能受体的细胞外信使参与其调节。这些受体包括P2X受体，它是一类配体门控离子通道，本文将对其在内分泌组织中的表达和作用进行综述。哺乳动物有七种嘌呤能受体亚基，分别命名为P2X1至P2X7，其中大多数亚基也在内分泌系统的分泌细胞和非分泌细胞中表达。已在神经内分泌下丘脑、垂体后叶和前叶、甲状腺、肾上腺、内分泌胰腺、性腺和胎盘中鉴定出功能性通道。天然通道能够促进可兴奋细胞和不可兴奋细胞通过其孔道内流钙，以及通过膜去极化增加可兴奋细胞的电活动。这导致钙瞬变的产生并刺激激素释放。P2X受体在内分泌系统中的表达和作用模式表明，局部产生的ATP可放大并同步单个细胞的分泌反应。
