Hoh Woo-Pil, Oh Tae-Ho
Department of Veterinary Internal Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Korea.
J Vet Sci. 2006 Mar;7(1):25-9. doi: 10.4142/jvs.2006.7.1.25.
This study was to determine the daily fluctuation of serum thyroxine (tT4), free thyroxine (fT4), 3,5,3'-triiodothyronine (T3) concentrations in healthy dogs. Thyroid function of these dogs was evaluated on the basis of results of TSH response test. Samples for the measurement of serum tT4, fT4, and T3 concentrations were obtained at 3- hour intervals from 8 : 00 to 20 : 00. Serum tT4, fT4, and T3 concentrations were measured by the enzyme chemiluminescent immunoassay (ECLIA). Mean T3 concentrations had no significant differences according to the sample collection time during the day. Mean tT4 and fT4 concentrations at 11 : 00 were 3.28 +/- 0.86 microg/dl and 1.30 +/- 0.37 ng/dl, respectively and mean tT4 and fT(4) at 14:00 were 3.54 +/- 1.15 microg/dl and 1.35 +/- 0.12 ng/dl, respectively. These concentrations were significantly high compared with tT4 and fT4 concentrations at 8:00, which were 1.75 +/- 0.75 microg/dl and 0.97 +/- 0.25 ng/dl, respectively (p < 0.05). According to the sample collection time, mean tT4 and fT4 concentrations changed with similar fluctuation during the day. Based on these results, it was considered that measurement of serum tT4 and fT4 concentrations from 11 : 00 to 14 : 00 might more easily diagnose the canine hypothyroidism in practice.
本研究旨在测定健康犬血清总甲状腺素（tT4）、游离甲状腺素（fT4）、3,5,3'-三碘甲状腺原氨酸（T3）浓度的每日波动情况。根据促甲状腺激素（TSH）反应试验结果评估这些犬的甲状腺功能。于8:00至20:00每隔3小时采集用于测定血清tT4、fT4和T3浓度的样本。采用酶化学发光免疫分析法（ECLIA）测定血清tT4、fT4和T3浓度。一天中不同采样时间的平均T3浓度无显著差异。11:00时的平均tT4和fT4浓度分别为3.28±0.86μg/dl和1.30±0.37ng/dl，14:00时的平均tT4和fT4浓度分别为3.54±1.15μg/dl和1.35±0.12ng/dl。与8:00时的tT4和fT4浓度（分别为1.75±0.75μg/dl和0.97±0.25ng/dl）相比，这些浓度显著更高（p<0.05）。根据采样时间，一天中平均tT4和fT4浓度呈现相似的波动变化。基于这些结果，认为在实际中于11:00至14:00测定血清tT4和fT4浓度可能更易于诊断犬甲状腺功能减退症。
