A monoclonal antibody that specifically recognizes the adrenocorticotropic receptor (ACTH) on rat adrenal cells was tested for hormonal activity. The antibody behaved as an agonist based on three different biological activities associated with ACTH. An antibody concentration of 16 μg/ml stimulated isolated rat adrenal cells to secrete 800 ng/104 cells of corticosterone with a concomitant 10-fold increase of cAMP to 30 pmol/105 cells. Antibody concentrations above 16 μg/ml inhibited mitotic activity in mouse Y-1 adrenal cells. A radioimmunoassay using an anti-ACTH antibody showed that the monoclonal anti-adrenocorticotropic receptor antibody and ACTH are antigenically related. These findings suggest that the anti-receptor antibody recognizes the ligand binding domain of the ACTH receptor.
Bibliographical noteFunding Information:
nett for expert technical assistance. This research was supported by NIDDKD grant DK39299 and PHS training grant AI107150-11.
- ACTH receptor
- Adenylate cyclase
- Complementary peptide
- Monoclonal antibody