The present invention, to a non-human animal that caused the (1) liver failure, human hepatic stem cells and / or hepatic progenitor cells and / or immature liver cells are transplanted, comprising that the cell is induced to differentiate into hepatocytes, methods of making a non-human animal with a humanized liver, prepared in (2) the process, human Non-human animals with a reduction liver, (3) the animals using, test method for examining the pharmacokinetics and / or liver toxicity of a substance, (4) liver damage human hepatic stem cells and the non-human animal that caused / or liver The transplanted progenitor cells and / or immature liver cells involves inducing differentiation into hepatocytes, methods of making human liver cells, and with human hepatocytes produced in (5) the method, the test substance drugs how to determine the kinetics and / or hepatotoxicity I provide,本発明は、(1)肝障害を起こした非ヒト動物へ、ヒト肝幹細胞及び/又は肝前駆細胞及び/又は未熟肝細胞を移植し、肝細胞に分化誘導させることを含む、ヒト化肝臓を持つ非ヒト動物の作製方法、(2)前記方法で作製した、ヒト化肝臓を持つ非ヒト動物、(3)前記動物を用いて、被験物質の薬物動態及び/又は肝毒性を調べる方法、(4)肝障害を起こした非ヒト動物へヒト肝幹細胞及び/又は肝前駆細胞及び/又は未熟肝細胞を移植し、肝細胞に分化誘導させることを含む、ヒト肝細胞の作製方法、及び、(5)前記方法で作製したヒト肝細胞を用いて、被験物質の薬物動態及び/又は肝毒性を調べる方法、を提供する。
