Tanaka T, Morita H, Koide H, Kawamura K, Takatsu T
Basic Res Cardiol. 1985 Mar-Apr;80(2):165-74. doi: 10.1007/BF01910464.
Experimental hyperthyroidism induced in rats by daily injections of 3,3',5,5'-tetraiode-L-thyroxine (0.5 mg/kg i.p.) for 14 days resulted in a significant increase in heart weight and heart weight/body weight ratio. Hemodynamic and morphological studies were performed in one group. Thyroxine-treated rats showed a characteristic cardiovascular hyperdynamic state, such as tachycardia and augmented rate of contraction, but no evidence of heart failure such as elevated end-diastolic pressures. The cardiac cells in hyperthyroid rats had a significantly larger diameter and more mitochondria than did those of the control rats. In another group the activities of cardiac enzymes involved in energy utilization and liberation were measured biochemically and compared with those of normal controls. Hyperthyroidism resulted in increased specific activity of cytochrome C oxidase and actomyosin ATPase in the myocardium. The specific activity of long-chain acyl-CoA synthetase, carnitine palmityl-transferase, carnitine acetyltransferase, malate dehydrogenase and citrate synthase showed a moderate to marked increment, whereas the specific activity of lactate dehydrogenase and pyruvate kinase remained at the control values. These results suggest that in hyperthyroid rat hearts the functions of both energy liberation and utilization systems are enhanced to meet the added workload. Moreover, the increased activity of the enzymes participating in fatty acid metabolism suggest that in thyroxine-induced hypertrophic and hyperdynamic rat hearts, fatty acids contribute more to the energy supply than do carbohydrates.
通过每天腹腔注射3,3',5,5'-四碘-L-甲状腺素（0.5毫克/千克），连续注射14天来诱导大鼠发生实验性甲状腺功能亢进，结果导致心脏重量以及心脏重量/体重比显著增加。对其中一组进行了血流动力学和形态学研究。经甲状腺素处理的大鼠呈现出典型的心血管高动力状态，如心动过速和收缩率增加，但未出现诸如舒张末期压力升高之类的心力衰竭迹象。与对照大鼠相比，甲状腺功能亢进大鼠的心肌细胞直径显著更大，线粒体更多。在另一组中，对参与能量利用和释放的心脏酶活性进行了生化测定，并与正常对照进行了比较。甲状腺功能亢进导致心肌中细胞色素C氧化酶和肌动球蛋白ATP酶的比活性增加。长链酰基辅酶A合成酶、肉碱棕榈酰转移酶、肉碱乙酰转移酶、苹果酸脱氢酶和柠檬酸合酶的比活性呈现出中度到显著的增加，而乳酸脱氢酶和丙酮酸激酶的比活性则维持在对照值水平。这些结果表明，在甲状腺功能亢进的大鼠心脏中，能量释放和利用系统的功能均得到增强，以满足增加的工作负荷。此外，参与脂肪酸代谢的酶活性增加表明，在甲状腺素诱导的肥厚性和高动力性大鼠心脏中，脂肪酸对能量供应的贡献大于碳水化合物。
