【摘要】 本文介绍水螅测试系统（Hydra Assay）中大鼠肝微粒体混合功能氧化酶（MFO）体外代谢活化体系的建立方法。其组成为0.06nmol P-450/ml,500μM NADPH,25μM MgCL₂。生化和生物测试结果均证明了这一体外代谢活化体系在水螅实验条件（20℃,pH7.0）下对前致畸原环磷酰胺的代谢活化能力。与未加代谢活化体系的水螅测试结果比较,加入代谢活化体系后环磷酰胺对水螅成体和胚胎的毒性分别增加了200倍和250倍。更多还原

【Abstract】 The proteratogen cyclophosphamide （CP）was tested in the hydra assay in the presen-ce and absence of an in vitro metabolic acti-vation package（MAP） consisting of rat hepaticmicrosomes （0.06 nmol P-450/ml）, 500umNADPH, and 25um MgCl₂. Bioactivation ofCP was confirmed under standard hydraassay conditions of pH7. 0 and 20℃, andcompared with activation at 37℃. Theresults show the bioactivation increased thetoxicity of CP by two orders of magnitude.The minimal effective concentration （MEC）in the adult and "artificial embryo" of theassay were decreased from 4000 μg/ml to 20μgCP/ml and from 1000μg/ml to 4.0μgCP/ml, respectively. Since hydra attonuateapparently lacks MFO capacity therebyfacilitating comparative studies employingmicrosomes of humans or any of thelaboratory mammals routinely used in dev-elopmental toxicity safety evaluations.更多还原