The distribution of immunoreactive angiotensins I and II extracted from rat brain.

A method was developed to measure immunoreactive angiotensin I and II extracted from rat brain tissue. The angiotensin-immunoreactive materials extracted from brain tissue resembled angiotensins I and II in many of their physiochemical properties. The concentration of angiotensin-immunoreactive materials was highest in extracts of pituitary, hypothalamus and thalamus. The concentrations of angiotensin-immunoreactive materials were not decreased in extracts of brain tissue from bilaterally nephrectomized rats. The concentrations of immunoreactive materials in extracts of pituitary far exceed those which could be accounted for by the blood and suggests that these endogenous peptides may regulate the neurosecretion of antidiuretic hormone.