The Use of Liver Microsome In-Vitro Methods to Study Toxicant Metabolism and Predict Species Efficacy

Abstract

Liver microsomes are used extensively in human pharmaceutical development to study the metabolism of compounds of interest; however, they are rarely part of the development of toxicants for the control of wildlife. Liver microsome samples from wildlife of interest would likely be harvested in the field without access to laboratory perfusion equipment. Therefore, the metabolic activity of microsomes from perfused and non-perfused livers was compared. There was no significant difference in diphacinone metabolism by liver microsomes from both perfused and non-perfused Wistar rat livers, although chlorophacinone metabolism was significantly different. There are often significant differences in metabolism between species that can be utilized to increase toxicant specificity. In this study bobwhite quail liver microsomes metabolized more diphacinone and chlorophacinone than both Wistar and brown rats. This information can be used during toxicant development to help determine the most sensitive species to toxicants of interest. Additionally, the effect of incubation time on toxicant metabolism was examined to determine optimal experimental conditions. The data from these experiments support the use of liver microsomes as a tool to be used during toxicant development to provide information that can be incorporated into whole animal studies.