Kjeldsen K, Everts M E, Clausen T
Pflugers Arch. 1986 May;406(5):529-35. doi: 10.1007/BF00583377.
Using a recently developed method based upon vanadate facilitated 3H-ouabain binding, the total concentration of 3H-ouabain binding sites was determined in biopsies of rat skeletal muscles containing varying proportions of slow-twitch fibres. In extensor digitorum longus, diaphragm, gastrocnemius and soleus muscles from mature (12-week-old) hyperthyroid rats the values obtained were respectively 2.6, 3.5, 5.1 and 9.8 times higher than those found in the same muscles from hypothyroid animals. This indicates that the effect of thyroid hormones is more pronounced on slow-twitch than on fast-twitch fibres. The changes in 3H-ouabain binding site concentration with thyroid status could not be accounted for by differences in affinity or the rate of 3H-ouabain binding. In young (4-5 week old) rats, where the K-content and the 3H-ouabain binding site concentration in muscle had been reduced by K-depletion, T3-pretreatment produced an even larger relative increase in the 3H-ouabain binding site concentration than in age-matched controls, but no increase in K-content. Therefore, the downregulation of 3H-ouabain binding sites seen during K-depletion cannot be attributed to a decreased response to thyroid hormones. In normal rats the marked stimulating effect of thyroid hormone on the synthesis of 3H-ouabain binding sites was not associated with any significant change in K-content, but clearly preceded by a significant (P less than 0.001) rise in the efflux of 86Rb.
使用一种基于钒酸盐促进3H-哇巴因结合的最新开发方法，测定了含有不同比例慢肌纤维的大鼠骨骼肌活检组织中3H-哇巴因结合位点的总浓度。在成熟（12周龄）甲状腺功能亢进大鼠的趾长伸肌、膈肌、腓肠肌和比目鱼肌中，获得的值分别比甲状腺功能减退动物相同肌肉中的值高2.6、3.5、5.1和9.8倍。这表明甲状腺激素对慢肌纤维的作用比对快肌纤维更明显。3H-哇巴因结合位点浓度随甲状腺状态的变化不能用亲和力或3H-哇巴因结合速率的差异来解释。在幼龄（4-5周龄）大鼠中，肌肉中的钾含量和3H-哇巴因结合位点浓度因钾缺乏而降低，T3预处理使3H-哇巴因结合位点浓度的相对增加甚至比年龄匹配的对照组更大，但钾含量没有增加。因此，钾缺乏期间观察到的3H-哇巴因结合位点的下调不能归因于对甲状腺激素反应的降低。在正常大鼠中，甲状腺激素对3H-哇巴因结合位点合成的显著刺激作用与钾含量的任何显著变化无关，但明显先于86Rb外流的显著（P小于0.001）升高。
