title: Investigation of the clinical significance of the growth hormone-releasing peptide-2 test for the diagnosis of secondary adrenal failure.
abstract: The aim of this study was to evaluate the ability of the growth hormone-releasing peptide-2 (GHRP-2) test to clinically diagnose hypothalamo-pituitary-adrenal (HPA) axis failure. We performed an insulin tolerance test (ITT), CRH stimulation test, and GHRP-2 test on 47 patients suspected of having a hypothalamo-pituitary disorder. Patients with pituitary disorders had significantly lower ACTH responses to the GHRP-2 test compared to patients with hypothalamic disorders and the control group. In contrast, peak cortisol levels in response to the GHRP-2 test were significantly lower in both hypothalamic and pituitary disorder cases compared with the control group. Assignment of a cut-off value of 11.6 μg/dL for the peak serum cortisol level demonstrated that the GHRP-2 test was able to predict secondary hypoadrenalism with 88.9% specificity and 89.7% sensitivity. The responses of ACTH and cortisol to the GHRP-2 test had no correlation to the CRH test, suggesting the involvement of a different mechanism of ACTH secretion. These results indicate that the GHRP-2 test may induce ACTH secretion from the pituitary gland through direct stimulation. Although the GHRP-2 test does not have the same predictive value as the insulin tolerance test (ITT), it has similar diagnostic potential as the CRH stimulation test for evaluating HPA axis failure.
authors.affiliation: Department of Diabetes and Endocrine Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima 890-8520, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Arimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hashiguchi
authors.forename: Kiyoaki
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shinnakasu
authors.forename: Aiko
authors.initials: A
authors.lastname: Arimura
authors.forename: Akira
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Takahisa
authors.initials: T
authors.lastname: Deguchi
authors.forename: Mika
authors.initials: M
authors.lastname: Habu
authors.forename: Singo
authors.initials: S
authors.lastname: Fujio
authors.forename: Kazunori
authors.initials: K
authors.lastname: Arita
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nishio
mesh_terms: D061605:Administration, Intravenous; D000293:Adolescent; D000309:Adrenal Insufficiency / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage; D004393:Dwarfism, Pituitary / Q000097:blood / Q000150:complications / Q000175:diagnosis; D005260:Female; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007027:Hypothalamic Diseases / Q000097:blood / Q000150:complications / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000008:administration & dosage*; D010912:Pituitary-Adrenal Function Tests / Q000379:methods*; D011237:Predictive Value of Tests; D055815:Young Adult
chemical_list: D009842:Oligopeptides; D019382:Human Growth Hormone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; C091874:growth hormone-releasing peptide-2; D006854:Hydrocortisone