MODERATE CALORIC RESTRICTION INCREASES TYPE-1 IGF RECEPTORS AND PROTEIN-SYNTHESIS IN AGING RATS
MODERATE CALORIC RESTRICTION INCREASES TYPE-1 IGF RECEPTORS AND PROTEIN-SYNTHESIS IN AGING RATS
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DOI：
10.1016/0047-6374(93)90035-p
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发表时间：
1993-10-01
影响因子：
5.3
通讯作者：
SONNTAG, WE
中科院分区：
文献类型：
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作者：
DCOSTA, AP;LENHAM, JE;SONNTAG, WE
胰岛素样生长因子-1 (IGF-1) 是一种合成代谢激素，可介导生长激素 (GH) 的作用，在老年动物中浓度较低。 GH 和 IGF-1 的减少似乎对衰老具有重要的生理后果，因为蛋白质合成随着年龄的增长而减少，并且 GH 和/或 IGF-1 的施用已被证明可以增加蛋白质合成。本研究旨在确定（a）组织蛋白合成率与血浆 IGF-1 浓度的年龄相关变化之间的关系，（b）组织中 1 型 IGF 受体密度，以及（c）已知可延长寿命的长期适度热量限制是否会影响这些关系。雄性棕色挪威大鼠从14周龄开始随意喂养或限制热量（60%随意）并在不同年龄处死。在随意喂养的动物中，血浆 IGF-1 浓度 (14%) 以及心脏 (36%) 和肝脏 (38%) 的蛋白质合成率均出现与年龄相关的下降。随着年龄的增长，所有组织中 1 型 IGF 受体密度保持恒定。热量限制动物的血浆IGF-1浓度比随意喂养的动物低33%至42%。然而，与随意喂养的动物相比，心脏和膈肌的蛋白质合成率增加了 70% 和 30%，并且这种增加与 1 型 IGF 受体密度增加 60% 至 100% 有关。这些数据表明，组织 1 型 IGF 受体的变化以及 IGF-1 的可用性可能是了解衰老期间或长期热量限制条件下 IGF-1 对蛋白质合成的调节的重要因素。
Insulin-like growth factor-1 (IGF-1) is an anabolic hormone that mediates the actions of growth hormone (GH) and is found at lower concentrations in aged animals. These decreases in GH and IGF-1 appear to have important physiological consequences for aging, since protein synthesis decreases with age, and administration of GH and/or IGF-1 has been shown to increase protein synthesis. The present study was designed to determine (a) the relationship between the age-related changes in rates of tissue protein synthesis and plasma IGF-1 concentrations, (b) type 1 IGF receptor density in tissues and (c) whether long-term moderate caloric restriction, which is known to increase life-span, affects these relationships. Male Brown Norway rats were fed ad libitum or caloric-restricted (60% ad libitum) from 14 weeks of age and sacrificed at different ages. In ad libitum fed animals there were age-related decreases in plasma IGF-1 concentrations (14%) and in the rates of protein synthesis of the heart (36%) and liver (38%). Type 1 IGF receptor density remained constant in all tissues with age. The caloric-restricted animals exhibited plasma IGF-1 concentrations 33 to 42% lower than the ad libitum fed animals. However, rates of protein synthesis increased by 70 and 30% in heart and diaphragm, and this increase was associated with 60 to 100% increases in type 1 IGF receptor densities when compared with ad libitum fed animals. These data suggest that alterations in tissue type 1 IGF receptors as well as availability of IGF-1 may be important factors in understanding the regulation of protein synthesis by IGF-1 during aging or under conditions of long-term caloric restriction.