Huang H H, Steger R W, Meites J
Exp Aging Res. 1980 Feb;6(1):3-12. doi: 10.1080/03610738008258342.
Serum TSH, T4 and T3 were measured by radioimmunoassay (RIA) in 20-24 month old and 6-8 month old Long-Evans male rats during basal conditions, and upon exposure to cold temperature (4 degrees C), injection of ovine TSH, thyroidectomy, and T4 or T3 treatment. Basal serum TSH values in the old and young rats were similar, but serum T4 and T3 levels in the old rats were significantly lower than in the young rats. No differences were observed in TSH release between old and young rats in response to cold temperature, but old rats whowed no rise in serum T4, TSH administration produced a significantly smaller increase in serum T4 in old rats, but similar increases in serum T3 in old and young rats. No differences were observed between old and young rats in the rise of serum TSH after thyroidectomy, or in the fall of serum TSH after T4 or T3 administration. These results are believed to indicate that the primary cause for reduced thyroid function in old rats lies in the thyroid gland itself.
采用放射免疫分析法（RIA）测定了基础状态下以及暴露于低温（4℃）、注射羊促甲状腺激素、甲状腺切除、T4或T3治疗后的20 - 24月龄和6 - 8月龄雄性Long-Evans大鼠的血清促甲状腺激素（TSH）、甲状腺素（T4）和三碘甲状腺原氨酸（T3）水平。老年和幼年大鼠的基础血清TSH值相似，但老年大鼠的血清T4和T3水平显著低于幼年大鼠。在低温刺激下，老年和幼年大鼠的TSH释放未观察到差异，但老年大鼠血清T4无升高，注射促甲状腺激素后老年大鼠血清T4的升高明显较小，但老年和幼年大鼠血清T3的升高相似。甲状腺切除术后血清TSH的升高，或T4或T3给药后血清TSH的下降，老年和幼年大鼠之间均未观察到差异。这些结果被认为表明老年大鼠甲状腺功能减退的主要原因在于甲状腺本身。
