*2.1. Experimental Animals*

Eight to 10 week-old male C57BL/6N mice (Janvier Labs, France) and 8- to 64-week-old Mdr2−/<sup>−</sup> mice and age-matched controls were used. The mice were housed under 12 h light/dark cycles at a controlled ambient temperature of 25 ◦C and fed ad libitum on a standard diet (Ssniff, Soest, Germany) with free access to water. Three to 5 mice were used for each time point and condition given in the result section. All experiments were approved by the local animal protection authorities (application number: 84-02.04.2017.A177).
