A corticotrophin-releasing factor: partial purification and amino acid composition

Abstract

Neurohypophysial and hypothalamic extracts contain a corticotrophin-releasing factor (CRF) that stimulates the release of adrenocorticotrophic hormone (ACTH) from isolated anterior-pituitary tissue. Serial paper chromatog-raphy in 4 different solvent systems was applied to the concentration of the CRF in Protopituitrin, a posterior-pituitary concentrate prepared as a stage in the purification of oxytocin and vasopressin. Purified CRF of neurohypophysial origin significantly increases the release of ACTH at doses as low as 1 [mu]mg. Purified CRF has the chemical and chromatographic properties of a peptide, distinct from oxytocin and vasopressin. After acid hydrolysis of purified CRF, the following amino acids were detected: cystine, aspartic acid, glutamic acid, glycine, proline, lysine, phenylalanine, alanine, serine and histidine.