Combined administration of human corticotropin-releasing factor and lysine vasopressin induces cortisol escape from dexamethasone suppression in healthy subjects.
Inadequate suppression of plasma cortisol after 1-2 mg dexamethasone is frequently observed in depressive patients. To further investigate the pathophysiology underlying cortisol nonsuppression after dexamethasone we compared cortisol and corticotropin (ACTH) response to human corticotropin-releasing factor (h-CRF), lysine vasopressin (LVP), and a concurrent administration of both peptides after pretreatment with 1.5 mg dexamethasone in six male controls. Neither h-CRF nor LVP were able to produce a marked elevation of dexamethasone suppressed plasma cortisol and ACTH. If both peptides were administered in combination, a substantial escape of plasma cortisol from dexamethasone suppression was observed. ACTH responses changed in concordance with those of cortisol indicating that the LVP-CRF interaction takes place at the pituitary level. Our finding is consistent with a multihormonal control of pituitary-adrenal activity and bears several implications for interpretation of dexamethasone suppression test results in depressive illness.
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008236:Lypressin / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male
D008236:Lypressin; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone