The ACTH ‘family tree’ of the rhesus monkey changes with development

THE pituitary hormone adrenocorticotrophin (ACTH) belongs to a ‘family’ of peptides derived from a common ‘stem hormone’ (Fig. 1). Depending on the way in which the stem hormone is cleaved, the various peptides are expressed and it is possible that qualitative changes in the expression of the peptide ‘family tree’ may be responsible for the alteration in fetal adrenal function which precedes birth1. We now report evidence for such changes in the rhesus monkey, which has a fetal adrenal comparable with that of man.