Tissue-like cultures of rat hepatocytes in study of phase I and phase II drug metabolism / 浙江大学学报·医学版

ABSTRACT

<p><b>OBJECTIVE</b>To investigate phase I and phase II enzyme activities in drug metabolism with tissue-like cultures of rat hepatocytes.</p><p><b>METHODS</b>The gel entrapment and spheroid culture of hepatocytes were used as tissue-like cultures and the monolayer culture was used as a control. The metabolism of phenacetin and 7-hydroxycoumarin (7-HC) was evaluated as the activities of phase I and phase II enzymes after incubated in medium for a period of time. The metabolites were assayed by HPLC. The hepatocytes were exposed to beta-naphthoflavone (BNF, 50 micromol x L(-1)) before the phase I and phase II enzyme activities were analyzed.</p><p><b>RESULT</b>In monolayer culture, phase I parameters decreased quickly and did not detected at d 5, and the phase II enzyme activities were not detected at d 7. In other two models of tissue-like cultures, the activities of phase I and phase II enzyme maintained at 32%-50% of the initial value at d 7. Paracetamol formation rates in spheroid culture maintained at 96% of that at d 1. The phase I enzyme activities of the spheroid culture were maintained from d 1 to d 3 at a level of 2.7-3.9-fold higher than the monolayer culture. After exposure to BNF the activities on phase I enzyme increased by about 2.5-fold (P <0.05) in all three culture models, while the increase in phase II enzyme was not significant.</p><p><b>CONCLUSION</b>The gel entrapment culture and spheroid culture are superior to the monolayer culture in maintenance of drug metabolic enzyme activities.</p>