Alhomida A S
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
In Vivo. 1998 Sep-Oct;12(5):553-8.
We have previously reported that theophylline administration (100 mg/kg bw/day) changes the levels of carnitine in the plasma and tissues of rats. The objective of this study was to investigate the effect of theophylline treatment on the activity of carnitine acetyltransferase (CAT) in rat kidney. CAT catalyzes the reversible transfer of short-chain acyl groups across the inner mitochodrial membrane. Results showed that a significant increase in the activity of CAT was observed in kidney theophylline-treated groups as compared to either control or placebo groups (P < 0.01). The ratio of total carnitine (TC) levels to CAT activity was significantly increased in theophylline-treated rats as compared to either control or placebo groups (P < 0.01). Moreover, the results showed a positive correlation between the kidney TC and CAT activity (P < 0.01), whereas they showed a positive correlation between plasma levels of TC and kidney levels of TC (P < 0.01). These changes in activity CAT as well as TC levels might be due to the result from theophylline-enhanced mobilization of lipid from adipose tissues which consequently stimulated an increased carnitine transport into the kidney tissues to form fatty acyl-carnitine groups for subsequent beta-oxidation inside the mitochondria.
我们之前曾报道，给予大鼠茶碱（100毫克/千克体重/天）会改变大鼠血浆和组织中的肉碱水平。本研究的目的是调查茶碱处理对大鼠肾脏中肉碱乙酰转移酶（CAT）活性的影响。CAT催化短链酰基可逆地穿过线粒体内膜。结果显示，与对照组或安慰剂组相比，经茶碱处理的肾脏组中CAT活性显著增加（P < 0.01）。与对照组或安慰剂组相比，经茶碱处理的大鼠中总肉碱（TC）水平与CAT活性的比值显著增加（P < 0.01）。此外，结果显示肾脏TC与CAT活性之间呈正相关（P < 0.01），而血浆TC水平与肾脏TC水平之间也呈正相关（P < 0.01）。CAT活性以及TC水平的这些变化可能是由于茶碱增强了脂肪组织中脂质的动员，从而刺激了更多肉碱转运到肾脏组织中，形成脂肪酰肉碱基团，以便随后在线粒体内进行β氧化。
