D'Costa A P, Ingram R L, Lenham J E, Sonntag W E
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1083.
J Reprod Fertil Suppl. 1993;46:87-98.
The decrease in tissue function that is observed in ageing animals has been linked to the decline in rates of protein synthesis. These changes may be caused, in part, by reduced secretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). It is well established that growth hormone-releasing hormone (GHRH) and somatostatin have an important role in the regulation of GH secretion and results from several studies suggest that an age-related increase in release of somatostatin has an important role in altering the secretion of GH. When the amounts of somatostatin mRNA were examined, there was a decrease in the aged rats but the amount of somatostatin mRNA bound to polysomes increased in these animals. This suggests that translational regulatory mechanisms are compromised in ageing animals. Moderate dietary restriction, which has been shown to increase life span, increases the amplitude of GH pulses and the capacity of tissues to synthesize protein. We have used the caloric restriction model to investigate the regulation and roles of GH and IGF-1 during ageing. Our results suggest that neuroendocrine regulation of GH secretion plays an important role in the process of biological ageing and that part of the beneficial effects of moderate dietary restriction may be mediated by altering the GH, IGF-1 axis.
在衰老动物中观察到的组织功能下降与蛋白质合成速率的降低有关。这些变化可能部分是由生长激素（GH）和胰岛素样生长因子1（IGF-1）分泌减少引起的。众所周知，生长激素释放激素（GHRH）和生长抑素在调节GH分泌中起重要作用，多项研究结果表明，生长抑素释放的年龄相关性增加在改变GH分泌方面起重要作用。当检测生长抑素mRNA的量时，老年大鼠的量减少，但这些动物中与多核糖体结合的生长抑素mRNA的量增加。这表明衰老动物的翻译调控机制受损。适度的饮食限制已被证明可以延长寿命，增加GH脉冲的幅度和组织合成蛋白质的能力。我们使用热量限制模型来研究衰老过程中GH和IGF-1的调节及其作用。我们的结果表明，GH分泌的神经内分泌调节在生物衰老过程中起重要作用，适度饮食限制的部分有益作用可能是通过改变GH-IGF-1轴介导的。
