抑制剂和刺激剂对年轻和老年大鼠离体肝细胞线粒体蛋白质合成的影响。

Effect of inhibitors and stimulators on isolated liver cell mitochondrial protein synthesis from young and old rats.

作者信息

Marcus D L, Lew G, Gruenspecht-Faham N, Freedman M L

出版信息

Exp Gerontol. 1982;17(6):429-35. doi: 10.1016/s0531-5565(82)80004-1.

Abstract

Mitochondria isolated from the livers of old rats (26-30 months) were found to incorporate 41% less leucine into mitochondrial proteins as compared to those from young rats (2-3 months). The initial rates of incorporation of label were 145 cpm/mg/min for the "old" animals, and 320 cpm/mg/min for the young animal. No difference in either amino acid pool size or leakage of label through the mitochondrial membrane was detected in the two age groups. Young rats were treated in vivo with cycloheximide (10 mg/kg) followed by isolation and incubation of their mitochondria in vitro two hours later. There was a two-fold increase in incorporation of leucine into mitochondrial proteins. In contrast, mitochondria isolated from old rats showed a markedly blunted response to cycloheximide pre-treatment. When mitochondria isolated from young and old rats were exposed to inhibitors of mitochondrial protein synthesis, alpha-alpha-dipyridyl (2 x 10(-4)M) and ethanol (0.15M), the old mitochondria showed greater susceptibility to inhibition. These results suggest that the control of the biosynthesis of mitochondrial proteins is altered in the old animals.

摘要

与年轻大鼠（2 - 3个月）肝脏分离出的线粒体相比，从老年大鼠（26 - 30个月）肝脏分离出的线粒体将亮氨酸掺入线粒体蛋白的量少41%。标记物掺入的初始速率，“老年”动物为145 cpm/mg/min，年轻动物为320 cpm/mg/min。在两个年龄组中，未检测到氨基酸池大小或标记物通过线粒体膜的泄漏有差异。给年轻大鼠在体内注射环己酰亚胺（10 mg/kg），两小时后分离并体外培养它们的线粒体。亮氨酸掺入线粒体蛋白的量增加了两倍。相比之下，从老年大鼠分离出的线粒体对环己酰亚胺预处理的反应明显减弱。当从年轻和老年大鼠分离出的线粒体暴露于线粒体蛋白合成抑制剂α - α - 联吡啶（2×10⁻⁴M）和乙醇（0.15M）时，老年线粒体对抑制作用更敏感。这些结果表明，老年动物中线粒体蛋白生物合成的调控发生了改变。