Van Hardeveld C, Clausen T
Am J Physiol. 1984 Oct;247(4 Pt 1):E421-30. doi: 10.1152/ajpendo.1984.247.4.E421.
In the perfused hindlimbs of hypo-, eu-, and hyperthyroid rats, high K+o (20 mM) markedly stimulated glucose uptake, lactate production, and O2-consumption to levels increasing with the thyroid status. At Ca2o+ less than 50 microM, all the responses became transient. In the hypothyroid preparations, caffeine (5 mM) produced no stimulation, but in those obtained from eu- and hyperthyroid rats, it increased all the metabolic parameters as well as K+ release in proportion to thyroid status. In isolated soleus and extensor digitorum longus muscles, both high K+o and caffeine stimulated 45Ca-efflux, with the response increasing in proportion to thyroid status. This stimulation was reduced by 70-100% with dantrolene (10(-5) M), which in earlier studies was shown to suppress the metabolic effects of high K+o and caffeine. High K+o also increased 45Ca-influx but produced no change in muscle calcium contents. The results support the idea that thyroid hormones control substrates availability and energy consumption in skeletal muscle by increasing the amount of sarcoplasmic reticulum and thereby the rate of Ca2+ mobilization into the cytosol.
在甲状腺功能减退、正常和甲状腺功能亢进大鼠的灌注后肢中，高钾离子浓度（20 mM）显著刺激葡萄糖摄取、乳酸生成和氧气消耗，且这些反应水平随甲状腺状态升高。当钙离子浓度低于50微摩尔时，所有反应均变为短暂性。在甲状腺功能减退的标本中，咖啡因（5 mM）未产生刺激作用，但在甲状腺功能正常和亢进大鼠的标本中，它会增加所有代谢参数以及钾离子释放，且与甲状腺状态成比例。在分离的比目鱼肌和趾长伸肌中，高钾离子浓度和咖啡因均刺激45钙外流，其反应与甲状腺状态成比例增加。丹曲林（10^(-5) M）可使这种刺激减少70 - 100%，在早期研究中已表明丹曲林可抑制高钾离子浓度和咖啡因的代谢作用。高钾离子浓度也增加45钙内流，但肌肉钙含量无变化。结果支持这样一种观点，即甲状腺激素通过增加肌浆网数量从而提高钙离子向胞质溶胶的动员速率，来控制骨骼肌中底物的可用性和能量消耗。
