Wyatt I, Doss A W, Zavala D C, Smith L L
Br J Ind Med. 1981 Feb;38(1):42-8. doi: 10.1136/oem.38.1.42.
Various amounts of paraquat (10(-5) to 10(-12) g) in 0.1 ml saline were instilled directly into the left bronchus of male adult rats. Gravimetric, macroscopic, and microscopic studies on the left lobe of the lung showed that 10(-5) g of paraquat produced lung oedema and macroscopic lesions two and 14 days after doing. The pathology of the lung was similar to that seen after systemic poisoning. When 10(-6) g of paraquat was instilled, some animals developed lung oedema and macroscopic lesions. Microscopic examination showed subtle changes in the parenchyma of the lung. With amounts of paraquat equal to or less than 10(-7) g (doses as little as 10(-12) g were used), no changes in the lung were seen. This is contrary to published accounts in which amounts as low as 10(-12) g (1 Pg) were reported to cause acute damage to the rabbit lung. When 3H paraquat was instilled into the left lobe (doses of 10(-5) to 10(-10) g were used), the loss of paraquat from the lung was biphasic. The initial half-life was less than one hour. The secondary phase obeyed first-order kinetics, and the half-life was dependent on the dose of paraquat instilled. This half-life was as short as 11 hours when 10(-5) g paraquat was instilled and was 76 hours after the instillation of 10(-10) g paraquat. The decrease in the half-life of the secondary phase with increasing doses of paraquat is possibly associated with the production of oedema or lung cell damage, or both. After the instillation of 10(-8) g 3H paraquat, the initial half-life was less than 15 minutes, and paraquat was detected in the urine and plasma at that time. This suggests that 50% of the instilled paraquat was rapidly absorbed from the lung into the plasma.
将不同量的百草枯（10⁻⁵至10⁻¹²克）溶于0.1毫升生理盐水中，直接注入成年雄性大鼠的左支气管。对肺左叶进行重量分析、宏观和微观研究表明，注入10⁻⁵克百草枯后2天和14天出现肺水肿和宏观病变。肺部病理学与全身中毒后的情况相似。当注入10⁻⁶克百草枯时，一些动物出现肺水肿和宏观病变。显微镜检查显示肺实质有细微变化。当百草枯量等于或小于10⁻⁷克（使用的剂量低至10⁻¹²克）时，肺部未见变化。这与已发表的报道相反，据报道低至10⁻¹²克（1皮克）的量会对兔肺造成急性损伤。当将³H标记的百草枯注入左叶（使用的剂量为10⁻⁵至10⁻¹⁰克）时，百草枯从肺中的损失是双相的。初始半衰期小于1小时。第二阶段符合一级动力学，半衰期取决于注入的百草枯剂量。当注入10⁻⁵克百草枯时，该半衰期短至11小时，注入10⁻¹⁰克百草枯后为76小时。随着百草枯剂量增加，第二阶段半衰期的缩短可能与水肿的产生或肺细胞损伤或两者都有关。注入10⁻⁸克³H标记的百草枯后，初始半衰期小于15分钟，此时在尿液和血浆中检测到百草枯。这表明注入的百草枯中有50%迅速从肺吸收到血浆中。
