Ianuzzo C D, Chen V, O'Brien P, Keens T G
J Appl Physiol Respir Environ Exerc Physiol. 1984 Jan;56(1):117-21. doi: 10.1152/jappl.1984.56.1.117.
This study examined the effects of long-term experimental dysthyroidism on the enzymatic character of the costal diaphragm and selected respiratory parameters. Costal diaphragms from thyroidectomized (TX), euthyroid (EU), and hyperthyroid (HT) male albino rats were used. HT was induced by subcutaneous injections of triiodothyronine on alternate days for 6 wk. Minute ventilation was greater for the HT (70%) compared with the TX rats. The enzymatic potentials of glycolysis (28%), tricarboxylic acid cycle (30%), and fatty acid oxidation (16%) were significantly increased in the HT diaphragms, whereas the potentials were lower by a similar relative extent in the TX diaphragms. The proportion of alkali-labile fibers were greater in the TX and lower in the HT diaphragm. The shifts in heart and muscle lactate dehydrogenase isoenzyme activities were consistent with the fiber type changes. These findings show that dysthyroidism modifies the overall enzymatic capacity of the diaphragm (i.e., glycolysis, tricarboxylic acid cycle, and fatty acid oxidation) along with the proportion of alkali-labile to alkali-stable fiber types. These enzymatic changes are similar to those resulting from exercise training, tracheal banding, streptozotocin diabetes, and emphysema.
本研究考察了长期实验性甲状腺功能障碍对肋膈膜酶特性及选定呼吸参数的影响。使用了来自甲状腺切除（TX）、甲状腺功能正常（EU）和甲状腺功能亢进（HT）雄性白化大鼠的肋膈膜。通过每隔一天皮下注射三碘甲状腺原氨酸持续6周诱导产生甲状腺功能亢进。与TX大鼠相比，HT大鼠的每分通气量更大（70%）。HT肋膈膜中糖酵解（28%）、三羧酸循环（30%）和脂肪酸氧化（16%）的酶活性显著增加，而TX肋膈膜中的这些活性则以类似的相对幅度降低。TX肋膈膜中碱不稳定纤维的比例更高，而HT肋膈膜中则更低。心脏和肌肉乳酸脱氢酶同工酶活性的变化与纤维类型的变化一致。这些发现表明，甲状腺功能障碍会改变膈膜的整体酶活性（即糖酵解、三羧酸循环和脂肪酸氧化）以及碱不稳定纤维与碱稳定纤维类型的比例。这些酶变化与运动训练、气管结扎、链脲佐菌素诱导的糖尿病和肺气肿所导致的变化相似。
