Viticchi C, Grinta R, Piantanelli L
Centre of Biochemistry, Gerontological Research Department, INRCA, Ancona, Italy.
Gerontology. 1990;36(5-6):286-92. doi: 10.1159/000213213.
The influence of ageing on the ability of the brain cortex beta-adrenoceptors to be regulated by very short stimulation with thyroid hormones has been investigated. Experiments were performed in 3-, 10-, 17- and 22-month-old mice using both thyroxine (T4) and triiodothyronine (T3) as stimulators and analyzing beta-adrenergic receptor characteristics 15 and 60 min after hormone injection. Results showed that a statistically significant up-regulation is present in both young and old mice when treated with T3. On the contrary, after T4 injection only 3-month-old animals respond to such a short-term treatment, whereas older adult and old animals showed not statistically significant changes. Thus, the impairment in the T4-induced up-regulation starts already in adult mice and does not seem to further increase progressively with advancing age. From these findings it is suggested that the lack of responsiveness of beta-adrenoceptors to T4 but not to T3 stimulation in adult and old mice may be due to relatively early impairment in the transformation of T4 into T3.
研究了衰老对大脑皮质β-肾上腺素能受体受甲状腺激素极短时间刺激调节能力的影响。使用甲状腺素（T4）和三碘甲状腺原氨酸（T3）作为刺激剂，对3个月、10个月、17个月和22个月大的小鼠进行实验，并在激素注射后15分钟和60分钟分析β-肾上腺素能受体特征。结果表明，用T3治疗时，年轻和老年小鼠均出现统计学上显著的上调。相反，注射T4后，只有3个月大的动物对这种短期治疗有反应，而成年和老年动物则未显示出统计学上显著的变化。因此，T4诱导的上调受损在成年小鼠中就已开始，且似乎不会随着年龄的增长而进一步逐渐增加。从这些发现可以推测，成年和老年小鼠中β-肾上腺素能受体对T4而非T3刺激缺乏反应性，可能是由于T4转化为T3的过程相对较早受损所致。
