2024-03-29T13:41:55Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/675552022-11-17T02:08:08Zhdl_2115_20048hdl_2115_140Novel revelation of warfarin resistant mechanism in roof rats (Rattus rattus) using pharmacokinetic/pharmacodynamic analysisTakeda, KazukiIkenaka, YoshinoriTanikawa, TsutomuTanaka, Kazuyuki D.Nakayama, Shouta M. M.Mizukawa, HazukiIshizuka, MayumiWarfarinRodenticideDrug resistanceRattus rattusCytochrome P450Pharmacokinetics649Roof rats (Rattus rattus) live mainly in human habitats. Heavy use of rodenticides, such as warfarin, has led to the development of drug resistance, making pest control difficult. There have been many reports regarding mutations of vitamin K epoxide reductase (VKOR), the target enzyme of warfarin, in resistant rats. However, it has been suggested there are other mechanisms of warfarin resistance. To confirm these possibilities, closed colonies of warfarin-susceptible roof rats (S) and resistant rats from Tokyo (R) were established, and the pharmacokinetics/ pharmacodynamics of warfarin in rats from both colonies was investigated. R rats had low levels of warfarin in serum and high clearance activity. These rats can rapidly metabolize warfarin by hydroxylation. The levels of accumulation in the organs were lower than those of S rats. R rats administered warfarin showed high expression levels of CYP2B, 2C, and 3A, which play roles in warfarin hydroxylation, and may explain the high clearance ability of R rats. The mechanism of warfarin resistance in roof rats from Tokyo involved not only mutation of VKOR but also high clearance ability due to high levels of CYP2B, 2C and 3A expression possibly induced by warfarin. (C) 2016 Elsevier Inc. All rights reserved.ElsevierJournal Articleapplication/pdfapplication/pdfhttp://hdl.handle.net/2115/67555https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/67555/2/Pestic%20Biochem%20Physiol_v.134%20p.1-7_Manuscript%20%26%20Figure.pdfhttps://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/67555/1/Table%20S1-S4%20%26%20Figure%20S1-S4.pdf0048-3575AA00771389Pesticide Biochemistry and Physiology134172016-11enginfo:pmid/27914534info:doi/10.1016/j.pestbp.2016.04.004©2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/author