Regulation of glycogen synthesis in rat-hepatocyte cultures by glucose, insulin and glucocorticoids.
Regulation of glycogen synthesis in rat-hepatocyte cultures by glucose, insulin and glucocorticoids.
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葡萄糖、胰岛素和糖皮质激素对大鼠肝细胞培养物中糖原合成的调节。
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发表时间：
1979
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通讯作者：
C. Schudt
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作者：
C. Schudt
在不同条件下，对2日龄大鼠肝细胞原代培养中糖原含量及其合成速率的变化进行了评估。在无血清和无激素培养基中培养的肝细胞在10.3 mM葡萄糖下从糖原降解转变为糖原沉积。在用糖皮质激素预处理细胞后，在没有或存在胰岛素的情况下，该阈值分别降低到5.4或1.2 mM葡萄糖。经曲安奈德预处理后，糖原在10 mM葡萄糖存在下的合成速率由5 nmol × h-1 × mg蛋白-1提高到20 nmol葡萄糖× h-1 × mg蛋白-1。胰高血糖素预处理也显著提高后续糖原合成速率。胰岛素的加入使糖原的合成速度加快了两倍，与前处理无关。胰岛素浓度与糖原合成率之间的剂量-反应关系显示，在0.62 +/- 0.22 nM（平均+/- S.D.）胰岛素时，效果达到一半。用糖皮质激素、胰高血糖素、胰岛素或这些激素的组合预处理肝细胞并没有显著改变浓度，只有一半的效果。
The changes in glycogen content and in its rate of synthesis in two-day-old primary cultures of rat hepatocytes were assessed under various conditions. Hepatocytes cultivated in serum-free and hormone-free medium switch from glycogen degradation to glycogen deposition at 10.3 mM glucose. After pretreatment of the cells with glucocorticoids this threshold was reduced, in the absence or presence of insulin, to 5.4 or 1.2 mM glucose, respectively. The rate of glycogen synthesis in the presence of 10 mM glucose was amplified from 5 nmol x h-1 x mg protein-1 to 20 nmol glucose x h-1 x mg protein-1 after pretreatment with triamcinolone. Glucagon pretreatment also significantly increased the subsequent glycogen synthesis rate. Insulin addition accelerated glycogen synthesis about twofold regardless of the pretreatment. The dose-response relationship between insulin concentration and glycogen synthesis rate showed half-maximal effect at 0.62 +/- 0.22 nM (mean +/- S.D.) insulin. Pretreatment of hepatocytes with glucocorticoids, glucagon, insulin or combinations of these hormones did not significantly change the concentration which gives the half-maximal effect.