[How should the plasma ACTH level in treated Addison's disease patients be interpreted?].

The ACTH plasma levels of 73 treated Addisonian patients have been analysed and compared to those obtained in 40 normal subjects after metyrapone-induced nocturnal cortisol deprivation (75 to 700 pg/ml). Using this new criterion, it appears that patients with ACTH plasma levels lower than 75 pg/ml are most often over-treated; those with ACTH plasma levels between 75 to 700 pg/ml are most often well substituted; and those with ACTH plasma levels higher than 700 pg/ml are under-treated. In this latter group coincidental high plasma renin activity is generally present, pointing to the possible role of the renin-angiotensin system in maintaining high ACTH plasma levels.