Immunoreactive Acth and Cortisol Plasma Levels During Pregnancy. Detection and Partial Purification of Corticotrophin‐like Placental Hormone: The Human Chorionic Corticotropin (Hcc)

The high plasma cortisol and ACTH levels present in pregnant women as well as the non-parrallelism of their plasma extract dilution curves in comparison with the standard curve in the ACTH radioimmunoassay, are evidence for the presence of an ACTH-like substance during pregnancy which would interfere with the assay. Placental extracts were obtained by acid-acetone extraction, followed by partial purification with oxycellulose and by extraction with porous glass powder. A substance was detected which partially cross-reacted with synthetic human ACTH in the radioimmunoassay and which showed biological activity using the assay procedure described by Liscomb & Nelson. The data sustain the existence of an ACTH-like placental hormone: human chorionic corticotrophin (HCC).