STUDIES ON THE PRESENCE OF ANGIOTENSIN-II IN RAT-BRAIN

Angiotensin[A]II-like immunoreactivity was extracted from brains of bilaterally nephrectomized rats with several different extraction procedures (90% methanol, distilled water, 6 M urea, 0.1 N HCl, and 2 M acetic acid). The activity was measured with radioimmunoassays using 3 different antisera, 2 of which had been used previously for immunocytochemical studies. With none of the extraction procedures or antisera employed was > 80 pg/g wet wt of AII-like immunoreactivity found. Analysis was undertaken with 2 different reverse-phase high-pressure liquid chromatography systems; in 1 of these the immunoreactivity did not coelute with AII or AIII. On the basis of its elution pattern from a molecular sieving column, the immunoreactivity seems to have a higher MW than AII. Evidently neurons in the brain do not synthesize and store AII.