Decrease in catechol-O-methyltransferase activity in the liver of streptozotocin-induced diabetic rats

被引:14
作者
Wang, JP
Liu, IM
Tzeng, TF
Cheng, JT [1 ]
机构
[1] Natl Cheng Kung Univ, Coll Med, Dept Pharmacol, Tainan 70101, Taiwan
[2] Mackay Mem Hosp, Dept Orthoped, Taipei, Taiwan
[3] Kaohsiung Med Univ, Coll Med, Dept Internal Med, Kaohsiung, Taiwan
关键词
catechol-O-methyltransferase; insulin; metanephrine; phlorizin;
D O I
10.1046/j.1440-1681.2002.03673.x
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
1. The present study compared the activity of catechol- O -methyltransferase (COMT) in the liver and plasma of streptozotocin (STZ)-induced diabetic rats with that in normal rats. The activity of COMT was estimated by the metabolism of noradrenaline to metanephrine (MN), both measured by high-performance liquid chromatography with electrochemical detection. 2. Formation of MN was decreased in the liver of STZ- diabetic rats compared with normal rats. The amount of MN was also decreased in plasma obtained from STZ-diabetic rats. A Michaelis-Menten plot showed a reduction in the maximum velocity and an increase in the K-m for COMT in liver samples from STZ-diabetic rats. 3. The role of hyperglycaemia in the lowering of COMT activity was then investigated using phlorizin or insulin at doses sufficient to normalize plasma glucose from STZ-diabetic rats. Both insulin and phlorizin treatment of STZ-diabetic rats for 4 days restored the activity of COMT to that seen in normal rats. Thus, correction of hyperglycaemia in STZ-diabetic rats can reverse the decrease in COMT activity. The activity of COMT is lower in STZ-diabetic rats than in normal rats mainly due to the higher plasma glucose.
引用
收藏
页码:419 / 422
页数:4
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