ACTH secretory responsiveness of pituitary adrenotroph cell tumor to adrenocorticotropin-releasing factor in Cushing's disease and Nelson's syndrome.

ACTH-secretory responsiveness of the adrenotroph cell tumors to the exogenous CRF was evaluated in 4 cases of Cushing's disease and 3 cases of Nelson's syndrome. Significantly exaggerated ACTH release was evoked by the intravenous injection of CRF in all 3 cases of Nelson's syndrome, but in Cushing's disease there seemed to be an individual difference in the sensitivity of the pituitary to CRF, probably depending on the functional activity of hypothalamo-pituitary axis.