Autoimmune hypophysitis is a chronic inflammation of the pituitary gland caused or accompanied by autoimmunity. It has traditionally been considered a rare disease but reporting has increased markedly in recent years. Hypophysitis, in fact, develops not uncommonly as a "side effect" in cancer patients treated with antibodies that block inhibitory receptors expressed on T lymphocytes, such as CTLA-4 and PD-1 receptors. Autoimmune hypophysitis can be induced experimentally by injecting mice with pituitary proteins mixed with an adjuvant. In this video article we demonstrate how to extract proteins from mouse pituitary glands and how to prepare them in a form suitable for inducing autoimmune hypophysitis in SJL mice.