Tanaka Y
Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Nihon Naibunpi Gakkai Zasshi. 1988 Mar 20;64(3):225-36. doi: 10.1507/endocrine1927.64.3_225.
To asses the changes in thyroid hormone metabolism after the onset of acute myocardial infarction (AMI), serum T4 and T3 levels were serially measured for 24 hours after the coronary artery ligation in dogs. The effect of thyroid hormone administration on hemodynamics in these dogs were also studied to clarify the possible usefulness of thyroid hormone therapy in nonthyroidal illness (NTI). Dogs were anesthetized with ketamine using "Micro-Mini" drip administration. Coronary artery ligation was performed in 8 dogs (MI group) Open chest operation was performed in 8 dogs, but their coronary arteries were not ligated and were used as control (cont. group). Blood samples were drawn before and 1, 3, 6, 12, 18 and 24 hours after coronary artery ligation, and serum levels of T4 and T3 were measured using the TDX T4 system and a commercial RIA kit, respectively. Various hemodynamic parameters (heat rate, mean blood pressure, max dp/dt, left ventricular end-diastolic pressure, cardiac output) were measured at the same time mentioned above. All the hemodynamic parameters remained within normal range for 24 hours in the control group. Serum T4 and T3 levels, however, showed slight, but significant decreases due to general anesthesia and open chest operation in the control group. On the other hand, hemodynamic parameters were maintained in the normal ranges only for 12 hours, and gradually deteriorated in the MI group. Moreover, it was remarkable that both T4 and T3 levels were decreased immediately after the ligation in this group, T4 being less than 0.1 micrograms/dl and T3 less than 10 ng/dl. They continued to show the low values thereafter. When T4 (30 micrograms/24 hours), and T3(7, 14 or 21 micrograms/24 hours) were continuously infused intravenously for 24 hours after the coronary artery ligation in 10 dogs, serum T4 levels were maintained in the normal range of the dog (1.5-3.6 micrograms/dl) and the serum T3 levels were increased to the low normal range. However, there were no significant differences in hemodynamic indices between the thyroid hormone treated groups and the non-treated group. These data show that T4 and T3 concentrations decrease prior to the deterioration of cardiac function. Moreover, the present findings also suggest that administration of thyroid hormone has no benefit in patients with NTI associated with low T4 and T3 levels.
为评估急性心肌梗死（AMI）发作后甲状腺激素代谢的变化，在犬冠状动脉结扎后的24小时内连续测定血清T4和T3水平。还研究了甲状腺激素给药对这些犬血流动力学的影响，以阐明甲状腺激素疗法在非甲状腺疾病（NTI）中的潜在效用。犬使用“微量-微型”滴注法用氯胺酮麻醉。8只犬进行冠状动脉结扎（MI组），8只犬进行开胸手术，但不结扎冠状动脉，用作对照（对照组）。在冠状动脉结扎前及结扎后1、3、6、12、18和24小时采集血样，分别使用TDX T4系统和商用放射免疫分析试剂盒测定血清T4和T3水平。在上述相同时间测量各种血流动力学参数（心率、平均血压、最大dp/dt、左心室舒张末期压力、心输出量）。对照组所有血流动力学参数在24小时内均保持在正常范围内。然而，对照组血清T4和T3水平因全身麻醉和开胸手术而出现轻微但显著的下降。另一方面，MI组血流动力学参数仅在12小时内维持在正常范围内，并逐渐恶化。此外，值得注意的是，该组结扎后T4和T3水平立即下降，T4低于0.1微克/分升，T3低于10纳克/分升。此后它们持续显示低值。当在10只犬冠状动脉结扎后静脉连续输注24小时T4（30微克/24小时）和T3（7、14或21微克/24小时）时，血清T4水平维持在犬的正常范围内（1.5 - 3.6微克/分升），血清T3水平升高至低正常范围。然而，甲状腺激素治疗组与未治疗组之间的血流动力学指标无显著差异。这些数据表明，T4和T3浓度在心脏功能恶化之前下降。此外，目前的研究结果还表明，对于T4和T3水平低的NTI患者，给予甲状腺激素并无益处。
