大鼠脑内游离细胞内和转运RNA氨基酸比活性及体内蛋白质合成的测量

Measurement of free intracellular and transfer RNA amino acid specific activity and protein synthesis in rat brain in vivo.

作者信息

Hargreaves-Wall K M, Buciak J L, Pardridge W M

机构信息

Department of Medicine, UCLA School of Medicine 90024-1682.

出版信息

J Cereb Blood Flow Metab. 1990 Mar;10(2):162-9. doi: 10.1038/jcbfm.1990.31.

DOI:10.1038/jcbfm.1990.31

PMID:2303533

Abstract

Brain protein synthesis was measured in anesthetized adult, male Sprague-Dawley rats by an in situ internal carotid arterial perfusion technique using [3H]leucine. The specific activity of free intracellular leucine and of tRNA leucine were determined by HPLC separation of phenylisothiocyanate (PITC) derivatives of amino acids. The specific activity of the leucyl-tRNA pool rapidly equilibrated with the free intracellular leucine pool within 2 min. The specific activity of the tRNA and free leucine pools in brain reached equilibrium by 10 min. Plasma amino acid specific activity, however, remained threefold higher than the specific activity of tRNA and free leucine pools. Estimates of protein synthesis were 0.62 +/- 0.06 nmol/min/g and were constant between 10 and 30 min of perfusion. The in situ perfusion model for protein synthesis described is a controlled system suited to measurements of protein synthesis in brain that can be applied to the study of brain metabolism under changing physiological conditions.

摘要

采用[³H]亮氨酸，通过原位颈内动脉灌注技术，在麻醉的成年雄性Sprague-Dawley大鼠中测量脑蛋白合成。游离细胞内亮氨酸和tRNA亮氨酸的比活性通过氨基酸苯异硫氰酸酯（PITC）衍生物的HPLC分离来测定。亮氨酰-tRNA池的比活性在2分钟内迅速与游离细胞内亮氨酸池达到平衡。脑中tRNA和游离亮氨酸池的比活性在10分钟时达到平衡。然而，血浆氨基酸比活性仍比tRNA和游离亮氨酸池的比活性高两倍。蛋白质合成的估计值为0.62±0.06 nmol/分钟/克，在灌注10至30分钟之间保持恒定。所描述的用于蛋白质合成的原位灌注模型是一个控制系统，适用于测量脑中的蛋白质合成，可应用于研究变化生理条件下的脑代谢。