Abstract

In respect to growth, the adrenal is a dynamic organ that requires constant stimuli from pituitary-derived POMC peptides to maintain its tonic state since either hypophysectomy or dexamethasone treatment results in rapid adrenal atrophy. It has been previously demonstrated that peptides derived from the N-terminus of the 16 kDa fragment of POMC not containing the gamma-MSH sequence are potent adrenal mitogens both in vitro and in vivo. However, since these shorter peptides are not found in the circulation, it has been suggested that they are generated by cleavage of the 16 kDa fragment by a specific protease expressed by the adrenal. This putative enzyme has recently been identified and this commentary describes the findings to date and highlights some of their possible implications.