内分泌
词汇介绍
拓展阅读
解析
Glycogen 英 /'glaɪkədʒ(ə)n/ 美 /'glaɪkodʒən/
释 义 n. 糖原；动物淀粉
例 句 The reason for this is that carbohydrate consumption stimulates insulin production, which aids the production of muscle glycogen.这是因为是碳水化合物的消耗刺激了胰岛素的分泌，后者对于肌肉糖原产生有帮助。
概述
概述
糖原是动物、真菌和细菌中多支链多糖的葡萄糖用作能量存储在的一种形式，多糖结构代表体内葡萄糖的主要存储形式。糖原起长期能量储备的两种形式之一的作用，另一种形式是甘油三酸酯存储在脂肪组织中（即人体脂肪）。
功能
①肝：当一餐含有碳水化合物或蛋白质的食物被食用和消化时，血糖水平会上升，并且胰腺会分泌胰岛素。门静脉的血糖进入肝细胞。胰岛素作用于肝细胞，刺激包括糖原合酶在内的几种酶的作用。只要胰岛素和葡萄糖都充足，就将葡萄糖分子添加到糖原链中。在餐后或“进食”状态下，肝脏从血液中吸收的葡萄糖多于其释放的葡萄糖。进餐后消化，葡萄糖水平开始下降，胰岛素分泌减少，糖原合成停止。当需要能量时，糖原分解并再次转化为葡萄糖。糖原磷酸化酶是糖原分解的主要酶。在接下来的8至12个小时内，源自肝糖原的葡萄糖是人体其余部分用作燃料的主要血糖来源。
②肌肉：肌肉细胞糖原似乎起肌肉细胞可用葡萄糖的立即储备源的作用。由于肌肉细胞缺乏葡萄糖6磷酸酶，而葡萄糖6磷酸酶是将葡萄糖传递到血液中所必需的，它们储存的糖原仅供内部使用，不能与其他细胞共享。这与肝细胞相反，肝细胞在需要时确实会将其储存的糖原分解为葡萄糖，并通过血流作为其他器官的能源燃料。
临床意义
①糖原代谢紊乱：糖原代谢异常的最常见疾病是糖尿病，其中由于胰岛素的异常含量，肝糖原可能会异常蓄积或消耗。正常葡萄糖代谢的恢复通常也使糖原代谢正常化。在胰岛素过多引起的低血糖症中，肝糖原水平很高，但是高胰岛素水平阻止了维持正常血糖水平所必需的糖原分解作用。胰高血糖素是这种类型的低血糖的常见治疗方法。
②糖原消耗和耐力运动：长途运动员（例如马拉松运动员，越野滑雪者和骑自行车的人）经常会发生糖原消耗，长期运动后，几乎所有运动员的糖原存储都被消耗掉了，而没有足够的碳水化合物消耗。糖原消耗可以通过三种可能的方式阻止。首先，在运动过程中，连续摄取具有最高可能转化为血糖（高血糖指数）的碳水化合物。其次，通过耐力训练的适应性训练和特殊的训练方法，身体可以调节I型肌纤维，从而提高燃料使用效率和工作负荷能力，从而增加用作燃料的脂肪酸的百分比，避免所有来源使用碳水化合物。第三，通过运动或饮食使糖原储备减少后，通过消耗大量碳水化合物，身体可以增加肌肉内糖原储备的储存能力。此过程称为碳水化合物装载。通常，碳水化合物源的血糖指数无关紧要，因为由于暂时性糖原耗竭，肌肉胰岛素敏感性增加。
复制标题洋地黄水提物改善链脲佐菌素诱导的糖尿病雄性Wistar大鼠的糖尿病
发表时间：2019-11-13
影响指数：3.4
作者： Adams Dele Moses
期刊：J Ethnopharmacol
Streptozotocin has been accepted as the first line choice for the induction of diabetes in experimental animals (Lenzen, 2008). It is selectively accumulated in the β-cells of the pancreas via the low-affinity GLUT2 glucose transporter in the plasma membrane. The transfer of the methyl group from streptozotocin to the DNA molecule results in a cascade of event, including activation of poly ADP-ribosylation which depletes NAD+ and ATP and generation of superoxide, hydrogen peroxide and hydroxyl radicals from the enhanced dephosphorylation of ATP. In addition, other toxic amount of nitric oxide generated by STZ also inhibits aconitase activity and participates in DNA damage. Protein glycosylation may be an additional damaging factor. All these inhibit the secretion of insulin that eventually gives rise to insulin-dependent diabetes mellitus. Normally, cells of the pancreas maintain blood glucose levels within a narrow limit by modulating the activity of the β-cells of the Islets of Langerhans through secretion of insulin. Therefore, the elevated blood glucose (hyperglycemia) in the male rats after the administration of STZ may be adduced to impairment in the release of insulin as a consequence of the destroyed βcells of Islets of Langerhans in the pancreas. In contrast, the lowered blood glucose levels and the ameliorative effects of the extract at 100 and 200 mg/kg body weight suggests that the extract increased the functional activity of the pancreas to secrete insulin. The enhanced secretion of insulin by the extract of D. exilis grains could be linked to the increase in pancreatic insulin in the present study. The extract-induced increase in the secretion of insulin by the pancreas as a response to the STZ-induced hyperglycermia might have promoted the up-take of glucose from the blood for energy production and thus restored the glycemic state of the animals. Therefore, the aqueous extract of D. exilis grains might possess an insulin-like effect or stimulate insulin secretion from β-cells. The findings with respect to the extract normalising hyperglycemia induced by STZ is similar to that reported by El-Quady et al. (2019).
译文
