흰쥐 분리 간세포에 있어서 딜티아젬의 간클리어런스에 미치는 페노바르비탈의 영향 = Effect of Phenobarbital on the Hepatic Clearance of Diltiazem in Isolated Rat Hepatocytes

다국어 초록 (Multilingual Abstract)

In order to study the effect of phenobarbital(PB) on the hepatic transport of diltiazem(DTZ), Ca^(2+) channel blocker, we used isolated hepatocytes of rat which was intraperitoneally pretreated with phenobarbital sodium(75㎎/㎏) for four days once a day. For the isolation of rat liver cells, a modification of the two step procedure of Seglen was used. DTZ was dissolved in incubation buffer to the final DTZ concentrations of 200, 400, 600, 800 and 1000 ng/㎖ in order to elucidate the uptake characteristics of DTZ by hepatocytes. Reactions were stopped at 10, 20, 30, 45, 60, 90, 120 and 300 sec. The initial velocity was determined by disappearance of diltiazem in the hepatocyte suspension. On the other hand, to determine the effect of PB on the in vitro hepatic intrinsic clearance of DTZ we obtained the metabolism rates of DTZ in the control and the PB-pretreated rat hepatocyte at various time intervals. According to pretreatment with PB, the size of hepatocyte and the amount of protein per 10^6 cells were significantly (p<0.01) increased from 26.92±0.1364 m to 35.31±1.00 m and from 468±6.5 ㎍/10^6 cells to 628.8±12.1 ㎍/10^6 cells, respectively. In the case of hepatic uptake of diltiazem. K_m was not different in the normalization by cell numbers and increased from 2.90 μM to 13.89 μM in the normalization by protein amount. V_(max) was increased regardless of normalization by protein amount and cell numbers, from 1.21μmole/min·㎎ protein to 3.96μmole/min·㎎ protein and from 2.38 μmole/min·10^6 cells to 2.83μmole/min 10^6 cells, respectively. The in vitro hepatic intrinsic clearance of DTZ was significantly (p<0.01) increased from 0.640±0.038 ㎖/mim·10^6 cells to 2.385±0.212 ㎖/min·10^6 cells due to PB-pretreatment. These results suggest that the uptake of DTZ by hepatocyte is extremely fast and PB enhances the hepatic intrinsic metabolic clearance of DTZ.