Isolation, structural elucidation and synthesis of a tetradecapeptide with in vitro ACTH-releasing activity corresponding to residues 33-46 of the α-chain of porcine hemoglobin

Abstract

A peptide found in acetic acid extracts of porcine hypothalami and capable of stimulating the release of ACTH in vitro was isolated in pure state, structurally identified as Phe-Leu-Gly-Phe-Pro-Thr-Thr-Lys-Thr-Tyr-Pre-Pro-His-Phe and synthesized. This tetradecapeptide, which corresponds to amino acid residues no. 33-46 in the sequence of the α-chain of porcine hemoglobin, probably represents an artefact of extraction or isolation procedures. Since this peptide stimulates ACTH release from rat pituitary fragments and from monolayer cultures of pituitary cells, but not in vivo, caution must be exercised in interpreting the results of in vitro assays for corticotropin releasing factor. © 1978.