Alhomida A S
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
J Enzyme Inhib. 1997 Dec;12(4):291-302. doi: 10.3109/14756369709035821.
The effects of oral theophylline administration (100 mg/kg b.w./day) on the activity of carnitine acetyltransferase (CAT) of rat heart for five-week interval treatment were studied. The result indicated that the body weights of placebo groups were not significantly changed as compared to control groups (P < 0.1), but theophylline treatment caused a significant decrease in the body weights of rat (P < 0.01) as compared to either control or placebo groups throughout the five-week interval treatments. Daily administration of theophylline to rats did not significantly affect heart weights as compared to either control or placebo groups (P < 0.1) for the five week-interval treatments. Our data indicated that the activity of CAT was not significantly changed in placebo groups as compared to control groups (P < 0.1), however, there was a significant increase in the activity of CAT in heart of theophylline-treated groups (P < 0.01) as compared to either control or placebo groups. The increase in the activity of CAT was noticed in the first three weeks of theophylline treatments followed by a gradual return toward normal activity by the fourth and fifth weeks of continued treatment. The observed changes in activity of CAT of heart might be due to theophylline-enhanced mobilization of lipid from adipose tissues which consequently stimulated increased L-carnitine transport into the heart tissues to form fatty acyl-carnitine groups for subsequent beta-oxidation inside the heart mitochondria. Accumulations of acyl-carnitine groups in heart mitochondria may increase the catalytic action of CAT and possible mechanisms are discussed.
研究了口服氨茶碱（100毫克/千克体重/天）对大鼠心脏肉碱乙酰转移酶（CAT）活性在为期五周的间隔治疗中的影响。结果表明，与对照组相比，安慰剂组的体重没有显著变化（P<0.1），但在整个五周的间隔治疗期间，与对照组或安慰剂组相比，氨茶碱治疗导致大鼠体重显著下降（P<0.01）。在为期五周的间隔治疗中，与对照组或安慰剂组相比，每日给大鼠服用氨茶碱对心脏重量没有显著影响（P<0.1）。我们的数据表明，与对照组相比，安慰剂组中CAT的活性没有显著变化（P<0.1），然而，与对照组或安慰剂组相比，氨茶碱治疗组心脏中CAT的活性显著增加（P<0.01）。在氨茶碱治疗的前三周观察到CAT活性增加，随后在持续治疗的第四周和第五周逐渐恢复到正常活性。心脏中CAT活性的观察到的变化可能是由于氨茶碱增强了脂肪组织中脂质的动员，从而刺激了L-肉碱向心脏组织的转运增加，形成脂肪酰肉碱基团，以便随后在心脏线粒体中进行β-氧化。心脏线粒体中酰基肉碱基团的积累可能会增加CAT的催化作用，并对可能的机制进行了讨论。
