EFFECT OF DESMOPRESSIN ON ACTH AND CORTISOL SECRETION IN STATES OF ACTH EXCESS

OBJECTIVE To assess the ability of desmopressin administration to stim ulate ACTH/cortisol secretion in patients with Gushing's disease, eith er before or after surgery, and in patients with other states characte rized by ACTH hypersecretion, and to compare the results with those ob tained after CRH testing, DESIGN AND SUBJECTS Plasma ACTH and serum co rtisol levels were evaluated after the administration of desmopressin (10 mu g i.v.), CRH (1 mu g/kg i.v.) and saline on different days in 1 7 patients with Gushing's disease, 1 with occult ectopic ACTH syndrome , 5 with Addison's disease, 3 who had been bilaterally adrenalectomize d for Gushing's syndrome and 4 normal subjects. After pituitary adenom ectomy desmopressin and CRH were administered again to 13 of the! pati ents who had undergone pituitary surgery for their Gushing's disease, RESULTS In 16 patients with Gushing's disease with microadenoma a posi tive ACTH/cortisol rise occurred in 11 patients after both desmopressi n and CRH, 2 other patients were responsive only to desmopressin and 2 only to CRH, while in 1 patient equivocal responses to both tests wer e found, The persistence of a hormonal response to desmopressin after pituitary adenomectomy for Gushing's disease correlated with unsuccess ful surgery, while, contrary to CRH, absent ACTH/cortisol rises were f ound in cured patients 1 and 12 months after operation, In 1 patient s uspected for ectopic ACTH hypersecretion, desmopressin and CRH adminis tration did not cause any ACTH/cortisol rise, Significant ACTH rises o ccurred after both desmopressin and CRH testing in patient with Addiso n's disease, All the 3 patients adrenalectomized for Gushing's syndrom e showed a rise of ACTH levels after CRH, while a similar response aft er desmopressin occurred in only one of them, CONCLUSIONS Desmopressin is able to stimulate ACTH and hence cortisol release in Gushing's dis ease, It may be a useful test in patients with doubtful responses to C RH test, in those exhibiting responses to CRH indistinguishable from t hose of normal subjects and ire the postoperative follow-up of Gushing 's disease. In some patients with abolished or reduced cortisol feed-b ack at hypothalamic-pituitary level the sensitivity of normal corticot rophs to desmopressin is enhanced.