담즙산 부하에 의한 흰쥐 간의 Cholinesterase의 합성 억제

Abstract

The possible mechanism of decrease of cholinesterase activity in cholestatic liver and serum was studied. Rats were divided into eight groups: Normal, sham operated control, bile duct obstruction (BDO) alone (BDO group), BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group). choledocho-caval shunt (CCS) operation (CCS group), CCS plus TCA injection (CCS plus TCA group), and CCS plus TUDCA injection (CCS plus TUDCA group). Cholinesterase activity was determined in the serum and liver cytosolic, mitochondrial and microsomal preparations isolated from the above experimental rats. The values of Km and Vmax in this hepatic enzyme were measured. The activity of liver microsomal cholinesterase showed a significant decrease in both the CCS and the BDO groups. And the activity of serum cholinesterase showed a marked decrease in both the CCS and the BDO groups. However, the cholinesterase activity in the serum and liver microsomal preparation fell more rapidly in the BDO group than the CCS group. Cholinesterase activities in liver cytosolic and microsomal preparations, and its Vmax values decreased significantly in both the CCS plus TCA group, and the BDO plus TCA group than that of each control group, such as CCS and BDO groups. On the other hand, the values of Km of the liver cytosolic and microsomal cholinesterase did not change in all the experimental groups. Serum cholinesterase activity decreased significantly in both the CCS plus TCA group and the BDO plus TCA group than that of each control group. However, these serum and hepatic enzymes activities did not change in both the CCS plus TUDCA group and the BDO plus TUDCA group. The above results suggest that TCA repress biosynthesis of cholinesterase in the liver. And the lowering of the serum enzyme activity is thought to be caused by a decrease of biosynthesis of this hepatic enzyme, which causes the enzyme to leak into the blood in small quantity.