AGT and diabetes insipidus: Finally, there is extensive physiological evidence for the function of the brain RAS system and its effects, for example, when renin or angiotensin II (Ang II) is administered centrally in the brain of rats, producing an increase in systemic blood pressure (BP) [15], or with the use of transgenic rats that are deficient in brain angiotensinogen, which develop diabetes insipidus with systemic BP reduction [16].