急性高氨血症状态下大脑线粒体支链氨基酸代谢的改变。

Alterations in mitochondrial branched-chain amino acid metabolism in brain in acute hyperammonemic states.

作者信息

Alexander J, Murthy C R

机构信息

Department of Physiology and Biophysics, University of Health Sciences, Chicago Medical School, IL 60064.

出版信息

Neurosci Lett. 1993 Jan 12;149(2):221-4. doi: 10.1016/0304-3940(93)90776-h.

DOI:10.1016/0304-3940(93)90776-h

PMID:8474697

Abstract

Production of 14CO2 and [14C]branched-chain keto acids (BCKA) was determined from [U-14C]branched-chain amino acids along with the activities of branched-chain amino acid transaminase (BCAA-T) and branched-chain keto acid dehydrogenase (BCKA-DH) in mitochondria isolated from the cerebral cortex of normal and hyperammonemic rats. Results indicated that the production of CO2, but not of keto acids, was suppressed while the activities of BCAA-T and BCKA-DH were not adversely affected in the mitochondria of hyperammonemic rats. Suppression in the oxidation of BCAA in hyperammonemic states was found to be due to increased efflux of BCKA from mitochondria.

摘要

从[U-¹⁴C]支链氨基酸中测定了¹⁴CO₂和[¹⁴C]支链酮酸（BCKA）的生成，同时还测定了从正常大鼠和高氨血症大鼠大脑皮质分离出的线粒体中支链氨基酸转氨酶（BCAA-T）和支链酮酸脱氢酶（BCKA-DH）的活性。结果表明，在高氨血症大鼠的线粒体中，CO₂的生成受到抑制，但酮酸的生成未受抑制，而BCAA-T和BCKA-DH的活性未受到不利影响。发现在高氨血症状态下支链氨基酸氧化的抑制是由于BCKA从线粒体中流出增加所致。