衰老过程中适应性机制的丧失。

Loss of adaptive mechanisms during aging.

作者信息

Adelman R C

出版信息

Fed Proc. 1979 May;38(6):1968-71.

Abstract

Factors contributing to modifications in the capability for enzyme adaptation as an expression of aging are reviewed. Specific examples of altered enzyme adaptations during aging include the responses of hepatic glucokinase activity to glucose and hepatic tyrosine aminotransferase activity to starvation in Sprague-Dawley rats. These impaired enzyme adaptations apparently are not the consequence of alterations in hepatic function during aging. Instead, they reflect disturbances in extrahepatic hormonal regulatory mechanisms. Specific examples include modifications in the control of circulating levels of insulin glucagon, corticosteroids, and thyroid hormones. Age-dependent changes in the regulation of circulating levels of insulin probably originate within the impaired ability of pancreatic islets of Langerhans to secrete the hormone in response to glucose. The rationale for exploiting this experimental approach as a means to understand biological aging is discussed.

摘要

本文综述了作为衰老表现的酶适应性能力改变的相关因素。衰老过程中酶适应性改变的具体例子包括，在斯普拉格-道利大鼠中，肝脏葡萄糖激酶活性对葡萄糖的反应以及肝脏酪氨酸转氨酶活性对饥饿的反应。这些受损的酶适应性显然不是衰老过程中肝功能改变的结果。相反，它们反映了肝外激素调节机制的紊乱。具体例子包括胰岛素、胰高血糖素、皮质类固醇和甲状腺激素循环水平控制的改变。胰岛素循环水平调节的年龄依赖性变化可能源于胰岛β细胞对葡萄糖反应分泌激素的能力受损。本文还讨论了利用这种实验方法作为理解生物衰老手段的基本原理。