Corticotropin-Releasing Factor Stimulation Test

To the Editor: 'The paper by Chrousos et al. on corlicolropinreleasing factor as an aid in the diagnosis of Cushing's disease (March 8 issue)¹ fails to take into consideration the fact that the pituitary tumors responsible for Cushing's disease are not homogeneous. As shown by Lamberts et al., a major proportion of these tumors are rich in neural tissue and behave differently in response to provocative and inhibitory stimuli than do antcrior-lobc tumors.² Such ACTH-sccreting ncurointermcdiate-lobc tumors are relatively refractory to glucocorticoid suppression but are suppressed by the dopamine agonist bromocriptine. We and others have found that possible neurointermediate-lobc tumors.