Masaoka T, Shirai M, Takagi H, Yamamoto M, Arishima K, Akahori F
Department of Veterinary Pharmacology, School of Veterinary Medicine, Azabu University, Kanagawa, Japan.
J Toxicol Sci. 1994 Aug;19(3):151-4. doi: 10.2131/jts.19.3_151.
Rats on day 21 of pregnancy received a subcutaneous injection of paraquat (2, 7 or 25 mg/kg). The inner diameter of the ductus arteriosus (DA) of their fetuses was measured using the whole-body freezing method 1, 3, 6 and 24 hours after injection. The 7 mg/kg dose group showed a significant constriction of the DA 3 hours after paraquat treatment. The 25 mg/kg dose group showed a significant constriction 3 and 6 hours after treatment. The constrictive effect was dose-dependent, that is, the magnitude of constriction observed 3 hours after paraquat injection was greater in the 25 mg/kg dose group than in the 7 mg/kg dose group. The 2 mg/kg dose group showed no significant change in the inner diameter of the DA at any point of measurement (1, 3, 6 and 24 hours after injection), compared to the saline treated controls. These results indicate that paraquat induces constriction of the fetal rat DA in a dose-dependent manner when administered in late stages of gestation, and that this effect of paraquat is not seen at a dose level of 2 mg/kg.
怀孕第21天的大鼠接受皮下注射百草枯（2、7或25毫克/千克）。在注射后1、3、6和24小时，使用全身冷冻法测量其胎儿动脉导管（DA）的内径。7毫克/千克剂量组在百草枯处理后3小时显示DA明显收缩。25毫克/千克剂量组在处理后3和6小时显示明显收缩。收缩效应呈剂量依赖性，即百草枯注射后3小时观察到的收缩程度在25毫克/千克剂量组中比在7毫克/千克剂量组中更大。与生理盐水处理的对照组相比，2毫克/千克剂量组在任何测量点（注射后1、3、6和24小时）的DA内径均无显著变化。这些结果表明，在妊娠后期给予百草枯时，其以剂量依赖性方式诱导胎鼠DA收缩，且在2毫克/千克剂量水平下未观察到百草枯的这种作用。
