Segal J, Troen B R, Ingbar S H
J Endocrinol. 1982 May;93(2):177-81. doi: 10.1677/joe.0.0930177.
Studies of the influence of age and sex on the concentrations of total thyroxine (T4) and 3,5,3'-tri-iodothyronine (T3) in serum and on the free T4 and free T3 indices, were conducted in Sprague-Dawley rats of the CD strain varying in age between 10 days and 12 months. Both sex- and age-related differences were found. In all age-groups studied, serum T4 concentrations were higher in the male than in the female, whereas serum T3 concentrations were higher in the female. In both sexes, concentrations of T4 and T3 in serum reached a peak early in life, between the first and second month of age, and declined thereafter. In addition, in both sexes the intensity of thyroid hormone binding, as judged from values of the in-vitro uptake of T3, did not change with age, suggesting that free T4 and T3 concentrations in the serum display the same sex differences and age-related changes as do the concentrations of total T4 and T3. It remains to be determined whether these sex- and age-related alterations in serum thyroid hormone concentration are expressed in differences in the activity of various thyroid hormone-dependent processes.
对10日龄至12月龄不同年龄的CD品系斯普拉格-道利大鼠，进行了年龄和性别对血清中总甲状腺素（T4）、3,5,3'-三碘甲状腺原氨酸（T3）浓度以及游离T4和游离T3指数影响的研究。研究发现了与性别和年龄相关的差异。在所有研究的年龄组中，雄性大鼠血清T4浓度高于雌性，而雌性大鼠血清T3浓度更高。在两性中，血清中T4和T3浓度在生命早期，即出生后第一和第二个月之间达到峰值，此后下降。此外，从T3体外摄取值判断，两性中甲状腺激素结合强度均不随年龄变化，这表明血清中游离T4和T3浓度与总T4和T3浓度一样，呈现相同的性别差异和与年龄相关的变化。血清甲状腺激素浓度这些与性别和年龄相关的改变是否在各种甲状腺激素依赖过程的活性差异中表现出来，仍有待确定。
