Disclosed are non-human mammals having a modified liver and methods of making such non-human mammals having a modified liver. The modified liver may be characterized by a non-germline, stable integration of a non-endogenous gene targeted to the liver of the non-human mammal. In certain aspects, the modified liver may have greater than at least 30% ablation of the endogenous hepatocyte population of the non-human mammal. In certain aspects, the non-human mammal may comprise at least 30% non-endogenous hepatocytes. The disclosed non-human mammals may be useful for pharmacology, drug absorption, distribution, metabolism, and excretion studies, collectively ADME and toxicology studies (ADME-tox), and/or drug screening.
