IMMUNOREACTIVE ACTH AND CORTISOL PLASMA LEVELS DURING PREGNANCY. DETECTION AND PARTIAL PURIFICATION OF CORTICOTROPHIN‐LIKE PLACENTAL HORMONE: THE HUMAN CHORIONIC CORTICOTROPIN (HCC)

Abstract

The high plasma Cortisol and ACTH levels present in pregnant women as well as the non-parallelism 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 Lipscomb & Nelson. The data sustain the existence of an ACTH-like placental hormone: human chorionic corticotrophin (HCC).