High affinity receptors for atrial natriuretic factor in PC12 cells

Specific receptors for atrial natriuretic factor (ANF) are characterized on PC12 cells (rat pheochromocytoma cell line). Radioiodinated synthetic ANF (Rat, 8-33) bound to a single class of high affinity binding sites with the Kd value of 6.7 × 10-10 M. The Bmax value was 29 fmol/105 cells and receptor density was calculated as 194,000 ± 20,000/cell. Photoaffinity labelling of ANF receptor specifically labelled two protein bands with apparent m.wt of 70,000 and 130,000. When the cells were incubated with the labelled ligand at 37°C the ligand was internalized. The rate of internalization increased in the presence of increased ligand concentration. ANF receptors on PC12 cells are reported for the first time which would provide a unique model for study of ANF-receptor interaction.