The combined corticotropin-releasing hormone/lysine vasopressin test discloses a corticotroph phenotype.
The combined administration of CRH and vasopressin to man now offers a powerful means to directly assess the pituitary corticotroph reserve. A double blind, randomized, placebo-controlled, cross-over trial offered the opportunity to perform the combined CRH/lysine vasopressin (LVP) test (100 micrograms ovine CRH, followed by 1 IU LVP over 15 min) on 3 different occasions without treatment in 10 normal male subjects. We showed that peak ACTH plasma levels after stimulation had wide intersubject variation, whereas they were remarkably stable in a given individual, with a mean intraclass correlation coefficient of 0.90 (95% confidence limits, 0.74-0.96). Peak ACTH plasma levels after CRH/LVP administration were not significantly correlated with basal plasma cortisol levels (r = -0.14; P > 0.45), but were strongly and inversely correlated with peak cortisol plasma levels after Cortrosyn stimulation (0.25 mg, im; r = -0.78; P < 0.0001). These data provide the first evidence that the overall hypothalamic-pituitary-adrenocortical axis has an intrinsic activity that is constitutively fixed for a given individual. The power of the combined CRH/LVP test offers a unique means to measure a genuine corticotroph phenotype in each individual.
Bertagna
X
X
Clinique des Maladies Endocriniennes et Métaboliques, ECLIMED Institut de Recherche Thérapeutique, Centre Hospitalier Universitaire, Cochin Université René Descartes, Paris, France.
Coste
J
J
Raux-Demay
M C
MC
Letrait
M
M
Strauch
G
G
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008236:Lypressin / Q000008:administration & dosage; D008297:Male; D010902:Pituitary Gland / Q000166:cytology / Q000502:physiology*; D008083:beta-Lipotropin / Q000097:blood
D008236:Lypressin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D008083:beta-Lipotropin; D006854:Hydrocortisone