Gebhardt R, Lippert C, Schneider A, Doehmer J
Physiologisch-chemisches Institut der Universität, 72076 Tübingen, Germany; Institut für Biochemie, Universitätsklinikum, 04103 Leipzig, Germany.
Toxicol In Vitro. 1999 Aug-Oct;13(4-5):639-43. doi: 10.1016/s0887-2333(99)00020-x.
Recombinant V79Mz cell lines stably co-expressing human CYP3A4 and human NADPH-cytochrome P450 oxidoreductase were used to compare testosterone metabolism under conventional stationary cultivation and under perifusion. In contrast to stationary culture, steady-state conditions for the production of 6beta-hydoxytestosterone were established in the perifusion system even when different concentrations of testosterone were infused sequentially. As a consequence of these favourable conditions, threefold higher maximal metabolic rates could be measured and kinetic constants could be determined more reproducibly than in stationary culture. The results indicate that CYP3A4 shows an autocatalytic reaction kinetic probably due to two binding sites for testosterone.
使用稳定共表达人CYP3A4和人NADPH - 细胞色素P450氧化还原酶的重组V79Mz细胞系，比较在传统静态培养和灌流培养条件下的睾酮代谢。与静态培养不同，即使依次注入不同浓度的睾酮，在灌流系统中也能建立6β - 羟基睾酮产生的稳态条件。由于这些有利条件，与静态培养相比，可以测量到高三倍的最大代谢率，并且动力学常数的测定更具可重复性。结果表明，CYP3A4可能由于睾酮的两个结合位点而呈现自催化反应动力学。
