1. Nuclei were isolated from rat liver and spleen by a standard technique which preserved the nuclear membrane. Electron microscopy, DNA/protein ratios and 5′-nucleotidase determinations confirmed the purity of the preparation.
2. Both liver and spleen nuclei specifically bound 125I-labelled angiotensin II (ANG II) with high affinity (Kd ≅ 1.0 nmol/l). Saralasin ANG III and ANG II 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 II receptors and raise important questions regarding the mechanism of action of this peptide.