Journal of Clinical Endocrinology & Metabolism, Vol 57, 1287-1291, Copyright © 1983 by Endocrine Society

ARTICLES

Immediate and delayed alterations of adrenocorticotropin and cortisol nyctohemeral profiles after corticotropin-releasing factor in normal man

G Copinschi, M Beyloos, D Bosson, D Desir, J Goldstein, C Robyn, P Linkowski, J Mendlewicz and JR Franckson

Intravenous injections of 50 micrograms corticotropin-releasing factor (CRF) to four normal men at 0900 and 2300 h were followed by significant plasma ACTH and cortisol elevations, without changes in GH and PRL concentrations. The responses were more easily assessed late in the evening than in the morning, when they were superimposed upon the spontaneous hormonal variations. The initial hormonal response was always followed by a period of decreased hormonal values compared to control patterns. The normal pituitary-adrenal response to CRF was blunted or abolished by prior administration of dexamethasone. These data suggest that exogenous administration or CRF-induced endogenous production of glucocorticoids modulates the sensitivity of corticotropic cells to the action of CRF. Since normal ACTH and cortisol secretory episodes are likely to obscure the effects of CRF, stimulation tests for clinical purposes should be performed during the quiescent period, i.e. late in the evening.

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