Frolkis V V, Valueva G V
Gerontology. 1978;24(2):81-94. doi: 10.1159/000212240.
The paper presents experimental data on extrathyroidal metabolism of thyroid hormones in rats of various ages (1.5--32 months):: T4-131I distribution in an organism, indices of T4 and T3 kinetics, tissue deiodinative capacity, formation of T4 tissue metabolism products and their clearance from cells and organism, T4 binding with tissue proteins. Essential changes in T4 peripheral tissue metabolism have been found with aging: T4 binding by tissues is decreased; T4 distribution space and metabolic clearance are increased; 125I clearance with urine is decreased; T4 half-time in blood remains unchanged; tissue deiodinative capacity is enhanced. Indices of T3 peripheral metabolism in old rats remain unchanged. All these findings result in shifts of the T4/T3 ratio in favour of the latter and in invariability of its content in tissues, alongside with a decrease of functional activity of the thyroid gland with aging.
本文展示了不同年龄（1.5 - 32个月）大鼠甲状腺激素甲状腺外代谢的实验数据：甲状腺激素T4 - 131I在生物体内的分布、T4和T3动力学指标、组织脱碘能力、T4组织代谢产物的形成及其从细胞和生物体内的清除、T4与组织蛋白的结合。研究发现，随着衰老，T4外周组织代谢发生了显著变化：组织对T4的结合减少；T4分布空间和代谢清除增加；尿中125I清除减少；T4在血液中的半衰期保持不变；组织脱碘能力增强。老年大鼠T3外周代谢指标保持不变。所有这些发现导致T4/T3比值向有利于T3的方向转变，且其在组织中的含量保持不变，同时随着衰老甲状腺功能活动降低。
