POMC and congenital adrenal hyperplasia: This means that the absolute amount of bioavailable cortisol was actually lower in Chronocort-treated patients with CAH, supporting the assumption that it was not the total amount of GC but the improved diurnal delivery of cortisol by Chronocort, and therefore the better control of the early morning ACTH and steroid surge, that results in the superior control of excess 17OHP and androgen production.