담즙울체간에서 carboxylesterase, arylesterase 및 cholinesterase의 활성변동을 알아보기 위하여 시행한 실험으로서 흰쥐의 총담관을 결찰하고 12시간부터 42일까지의 담즙울체간에서 세포질, mitochondria 및 microsome의 carboxylesterase, arylesterase 및 cholinesterase활성도를 측정하는 한편 혈청에서 이들 효소활성도도 함께 측정하였다. 또한 흰쥐의 총담관을 결찰한 후 14일 경과한 쥐의 담즙울체간에서 이들 효소의 $K_m$과 $V_{max}$를 측정하였으며 아울러 세포핵 및 핵외 RNA합성속도와 세포질, mitochondria 및 microsome의 단백합성속도를 측정하였다. 흰쥐 담즙울체간의 cytosolic 및 mitochondrial carboxylesterase 활성도는 총담관결찰 후 7일부터 42일까지 현저한 감소를 나타내었다. microsomal carboxylesterase활성도는 총담관결찰 후 1일부터 42일까지 현저한 감소를 나타내었다. 혈청의 carboxylesterase 활성도는 총담관결찰 후 3일부터 42일까지 현저한 감소를 나타내었다. 흰쥐 담즙울체간의 cytosolic 및 mitochondrial arylesterase활성도는 총담관결찰 후 14일부터 42일까지 현저한 감소를 나타내었다. 그러나 microsomal arylesterase 활성도는 총담관결찰 후 1일부터 42일까지 현저한 감소를 나타내었다. 혈청의 arylesterase 활성도는 실험 전기간 동안 현저한 감소를 나타내었다. 흰쥐 담즙울체간의 cytosolic cholinesterase 활성도는 실험 전기간 동안 별 변동이 없었다. 그러나 mitochondrial 및 microsomal cholinesterase 활성도는 각각 총담관결찰 후 14일부터 42일까지 그리고 12시간부터 42일까지 현저한 감소를 나타내었다. 혈청의 cholinesterase 활성도는 총담관결찰 후 1일부터 42일까지 현저한 감소를 나타내었다. 흰쥐의 총담관을 결찰한 후 14일 경과한 쥐의 담즙울체간에서의 carboxylesterase, arylesterase 및 cholinesterase의 $K_m$치는 변동이 없었다. 그러나 이들효소의 $V_{max}$치는 현저한 감소를 나타내었다. 흰쥐의 총담관을 결찰한 후 14일 경과한 쥐의 담즙울체간에서의 세포핵 RNA와 세포핵외 RNA합성속도는 모두 유의한 감소를 나타내었다. 흰 쥐의 총담판을 결찰한 후 14일 경과한 쥐의 담즙울체간에서의 세포질, mitochondria 및 microsome의 단백합성속도도 모두 유의한 감소를 나타내었다. 이상 결과로 보아 흰쥐 담즙울체간의 carboxylesterase, arylesterase 및 cholinesterase는 그 활성이 감소되는 효소이며 이들 효소의 활성감소는 담즙울체간에서 그 합성이 저하되어 나타난 결과라 생각된다.
A study was made on the changes of carboxylesterase, arylesterase and cholinesterase activities in cholestatic rat liver. The cytosolic, mitochondrial and microsomal carboxylesterase, arylesterase and cholinesterase activities were determined in the cholestatic rat liver induced by common bile duct ligation over a period of forty two days. The activities of these esterases in the serum were measured. The rats were sacrificed on the 14th day after common bile duct ligation for the values of the $K_m$ and $V_{max}$ in their hepatic esterases. The incorporation rates of orotic acid-(6)-$^{14}C$ into nuclear and extranuclear RNA in their wet liver and the incorporation rates of amino acid mixture-(U)-$^{14}C$ into protein of the cytosolic, mitochondrial and microsomal fractions in their liver were also measured. The activities of cytosolic and mitochondrial carboxylesterase of the cholestatic rat liver showed a remarkable decrease between the 7th and the 42nd days following the ligation of the common bile duct. On the other hand, the microsomal carboxylesterase activity in the cholestatic liver markedly decreased between the 1st and the 42nd days after the ligation. The carboxylesterase activity of the serum markedly decreased between the 3rd and the 42nd days after the ligation. The cytosolic and mitochondrial arylesterase activities in the cholesatatic liver had a marked diminution between the 14th and the 42nd days after the ligation, but the microsomal arylesterase activity in the cholestatic liver showed a marked decrease between the 1st and the 42nd days after the operation. The arylesterase activity in the serum showed a marked decrease throughout the experiments. The mitochondrial and microsomal cholinesterase activities of the cholestatic liver each showed a marked decrease between the 14th and the 42nd days and the 12th hour and the 42nd day respectively after the ligation. However, the cytosolic cholinesterase activity did not change. That of the serum cholinesterase also showed a marked decrease between the 1st and th 42nd days after the ligation. The values of Vmax of the cytosolic, mitochondrial and microsomal carboxylesterase and arylesterase, and of the mitochondrial and microsomal cholinesterase in cholestatic rat liver showed a marked decrease from the 14th day after the ligation, however, the values of $K_m$ of above hepatic esterases did not change. The incorporation rates of orotic acid-(6)-$^{14}C$ into nuclear and extranuclear RNA in cholestatic rat liver showed a significant diminution from the 14th day after the ligation. The incorporation rates of amino acid mixture-(U)-$^{14}C$ into protein of the cytosolic, mitochondrial and microsomal fractions in their liver had a marked diminution from the 14th day after ligation. Viewed from above results, carboxylesterase, arylesterase and cholinesterase in the liver with cholestasis seem to be decreasing activities of enzymes seemingly due to the decrement of biosynthesis.
