Specific nuclear binding of angiotensin II by rat liver and spleen nuclei.

1. Nuclei were isolated from rat liver and spleen by a standard technique which preserved the nuclear membrane. Electron microscopy, DNA/protein ratios and S'-nucleotidase determinations codfirmed the purity of the preparation. 2. Both liver and spleen nuclei specifically bound '251-labelled angiotensin I1 (ANG 11) with high affinity (Kd Z 1-0 nmol/l). Saralasin ANG I11 and ANG I1 competed with tracer for ligand whereas ANG I did so less effectively and neurotensin not at all. 3. These results suggest the presence of specific nuclear intracellular ANG I1 receptors and raise important questions regarding the mechanism of action of this peptide.