P. Colombo et al., Usefulness of the desmopressin test in the postoperative evaluation of patients with Cushing's disease, EUR J ENDOC, 143(2), 2000, pp. 227-234
Objective: To evaluate the plasma ACTH and serum cortisol responses to desm
opressin in patients with Gushing's disease either before or after pituitar
y adenomectomy during long-term follow-up, and to compare the results with
those obtained after corticotrophin-releasing hormone (CRH) testing.
Design: Plasma ACTH and serum cortisol concentrations were evaluated after
the administration of desmopressin (10 mu g i.v.) or CRH (1 mu g/kg i.v.) i
n 34 patients with Gushing's disease, Twenty-four patients with active Gush
ing's disease were evaluated both before and after transsphenoidal pituitar
y surgery (TSS): these patients were followed up for 1-36 months. Ten patie
nts were studied only after a long-term period (1-19 years, median 4 years)
after TSS (six patients), TSS plus external pituitary irradiation (three p
atients) and TSS plus radiosurgery (one patient).
Results: In 24 patients with active Gushing's disease a significant ACTH/co
rtisol response (P < 0.001) was induced by either desmopressin (ACTH fi om
a baseline of 15.3 +/- 2.7pmol/l to a peak of 40.9 +/- 7.3 pmol/l: cortisol
from 673 +/- 59 nmol/l to 1171 +/- 90 nmol/l) or CRH (ACTH from a basal of
14.2 +/- 2.5 pmol/l to a peak of 47.2 +/- 7.7 pmol/l: cortisol from 672 +/
- 50nmol/l to 1192 +/- 80 nmol/l). In all patients a positive cortisol resp
onse to desmopressin was found. After pituitary adenomectomy the 14 'cured'
patients were followed up for 1-36 months; desmopressin administration nev
er induced ACTH or cortisol responsiveness in any patient. In contrast, a p
rogressive recovery of ACTH and cortisol responses after CRH was observed a
t different intervals of time in all patients but one,
Five patients, in whom the cortisol concentration only normalized after sur
gery, showed a persistent responsiveness to desmopressin, and two of them r
elapsed 12 and 24 months later. In five patients who were not cured, the ho
rmonal responsiveness to either CRH or desmopressin was similar before and
after operation. Of 10 patients studied only after long-term follow-up, six
were cured and a normal response to CRH was present, whereas no changes in
ACTH/cortisol concentrations were induced by desmopressin. The other four
unsuccessfully operated patients underwent pituitary irradiation and showed
different and equivocal hormonal responses to desmopressin and to CRH.
Conclusions: During the postoperative follow-up of patients with Gushing's
disease, the maintenance or the disappearance of the hormonal response may
be related to the persistence or the complete removal of adenomatous cortic
otrophs, respectively. It is suggested that desmopressin test should be per
formed in the preoperative evaluation and follow-up of patients with ACTH-d
ependent Gushing's syndrome.