Physiologically based pharmacokinetic (PBPK) models have been applied to simulate the absorption, distribution, metabolism, and elimination of various toxicants in fish. This approach allows for considering metal accumulation in intestinal parasites. Unlike “semi” physiologically-based models developed for metals, metal accumulation in fish was characterised based on metal-specific parameters (the fraction in blood plasma and the tissue-blood partition coefficient) and physiological characteristics of the fish (the blood flow and the tissue weight) in our PBPK model. In the model, intestinal parasites were considered a sink of metals from the host intestine. The model was calibrated with data for the system of the chub Squalius cephalus and the acanthocephalan Pomphorhynchus tereticolliis. Metal concentrations in this fish-parasite system were monitored in Ag and Co treatments in duplicate during a 48-day exposure phase (Ag and Co were added to tap water at concentrations of 1 and 2 µg/L, respectively) and a 51-day depuration phase. Their concentrations in the gills increased during the exposure phase and decreased in the depuration phase. A similar pattern was observed for Ag concentrations in other chub organs, while a relatively stable pattern for Co indicates regulations in the accumulation of essential metals by chubs. The metals were taken up by the acanthocephalans at similar rate constants. These results indicate that metal availability to parasites, which is determined by the internal distribution and fate, is critical to metal accumulation in the acanthocephalans. The high concentration of Ag in the liver as well as the high rate of Ag excretion from the liver to the intestine might contribute to higher concentrations of metals in the bile complexes in the intestine, which are available to the parasites, but not to the reabsorption by the host intestine. The opposite pattern might explain the lower availability of Co to the acanthocephalans.

已应用基于生理的药代动力学 (PBPK) 模型来模拟鱼类中各种毒物的吸收、分布、代谢和消除。这种方法允许考虑肠道寄生虫中的金属积累。与为金属开发的“半”基于生理学的模型不同，鱼体内的金属积累是基于金属特定参数（血浆中的分数和组织-血液分配系数）和鱼的生理特征（血流和组织重量）在我们的 PBPK 模型中。在该模型中，肠道寄生虫被认为是来自宿主肠道的金属汇。该模型已使用鲢鱼和棘头鲀系统的数据进行校准。. 在 48 天的暴露阶段（Ag 和 Co 分别以 1 和 2 µg/L 的浓度添加到自来水中）和 51 天的 Ag 和 Co 处理中，对这种鱼类寄生虫系统中的金属浓度进行了两次监测。净化阶段。它们在鳃中的浓度在暴露阶段增加，在净化阶段降低。其他鲢鱼器官中的银浓度也观察到类似的模式，而钴的相对稳定模式表明鲢鱼对必需金属积累的调节。金属以相似的速率常数被棘头动物吸收。这些结果表明，由内部分布和命运决定的寄生虫对金属的可用性对棘头动物中的金属积累至关重要。肝脏中高浓度的 Ag 以及从肝脏到肠道的高 Ag 排泄率可能导致肠道中胆汁复合物中的金属浓度更高，这些金属可用于寄生虫，但不能用于重吸收通过宿主肠道。相反的模式可能解释了 Co 对棘头动物的可用性较低。