A radiometric assay for the total metabolism of antipyrine in vitro by hepatic microsomal preparations has been developed. 2. Apparent Km and V values for the process were determined in rats, rabbits and in a marsupial (the quokka; Setomix brachyurus). Km values were similar in rats and rabbits (3.5 and 5 mM respectively) but were somewhat lower in quokkas (1.4--1.5 mM). Estimates of V ranged from 49--64 nmol/mg microsomal protein/10 min and were similar in all three species. Pretreatment of rabbits with phenobarbitone significantly increased V without change in Km. 3. Studies in individual rabbits and quokkas showed a good correlation between rate of hepatic microsomal metabolism of antipyrine in vitro and its half-life in vivo.
摘要
已开发出一种用于体外通过肝微粒体制剂测定安替比林总代谢的放射性测定法。2. 在大鼠、兔子和一种有袋动物（短尾矮袋鼠；Setomix brachyurus）中测定了该过程的表观 Km 和 V 值。大鼠和兔子的 Km 值相似（分别为 3.5 和 5 mM），但短尾矮袋鼠的 Km 值略低（1.4 - 1.5 mM）。V 的估计值范围为 49 - 64 nmol/mg 微粒体蛋白/10 分钟，在所有三个物种中相似。用苯巴比妥预处理兔子可显著增加 V 而 Km 不变。3. 对个体兔子和短尾矮袋鼠的研究表明，体外肝微粒体代谢安替比林的速率与其体内半衰期之间具有良好的相关性。
