Goya R G, Gagnerault M C, Sosa Y E, Bevilacqua J A, Dardenne M
Neuroendocrine Gerontology Laboratory, IMBICE, La Plata, Argentina.
Neuroendocrinology. 1993 Sep;58(3):338-43. doi: 10.1159/000126559.
It is well-established that the activity of the endocrine thymus is under neuroendocrine control. In particular, growth hormone (GH) and thyroxine (T4) have been shown to be capable of reconstituting thymus function in hormone-deficient animals. It was therefore of interest to assess the effect of combined administration of ovine GH (0.1 mg/100 g BW/day) and T4 (10 micrograms/100 g BW/day) on serum thymulin levels in young (5 months), old (21 months) and senescent (29-30 months) male Sprague-Dawley rats. Age-matched controls received 0.1 mg bovine serum albumin/100 g BW daily during the same period (14 days). Prolactin (Prl), GH, T4 and triiodothyronine (T3) were measured in serum by radioimmunoassay, whereas serum thymulin was determined by rosette bioassay. As expected, GH and T4 were lower in the old and senescent controls whereas serum Prl displayed a slight age-related increase. No age changes were detected in serum T3. Hormone-treated animals showed supraphysiologic levels of both T4 and T3, but serum levels were comparable among the three treated age groups for each thyroid hormone. Endogenous GH levels were moderately elevated in the treated rats. In the control rats serum thymulin showed a marked reduction from 5 to 21 months of age but no further reduction was observed between 21 and 29-30 months. Hormone treatment induced a mean relative increase (% increase relative to age-matched controls) in serum thymulin of 44, 38 and 48% in young, old and senescent rats, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
内分泌胸腺的活动受神经内分泌控制，这一点已得到充分证实。特别是，生长激素（GH）和甲状腺素（T4）已被证明能够在激素缺乏的动物中重建胸腺功能。因此，评估联合给予绵羊GH（0.1毫克/100克体重/天）和T4（10微克/100克体重/天）对年轻（5个月）、老年（21个月）和衰老（29 - 30个月）雄性Sprague-Dawley大鼠血清胸腺素水平的影响具有重要意义。同期，年龄匹配的对照组每天接受0.1毫克牛血清白蛋白/100克体重（共14天）。通过放射免疫测定法测量血清中的催乳素（Prl）、GH、T4和三碘甲状腺原氨酸（T3），而通过玫瑰花结生物测定法测定血清胸腺素。正如预期的那样，老年和衰老对照组中的GH和T4水平较低，而血清Prl则呈现出与年龄相关的轻微升高。血清T3未检测到年龄变化。激素处理的动物显示T4和T3的水平均高于生理水平，但每个甲状腺激素的血清水平在三个处理的年龄组中相当。处理后的大鼠内源性GH水平适度升高。在对照大鼠中，血清胸腺素在5至21月龄之间显著降低，但在21至29 - 30月龄之间未观察到进一步降低。激素处理分别使年轻、老年和衰老大鼠的血清胸腺素平均相对增加（相对于年龄匹配对照组的增加百分比）44%、38%和48%。（摘要截于250字）
