title: Diagnostic usefulness of the growth hormone-releasing peptide-2 test as a substitute for the insulin tolerance test in hypopituitarism.
abstract: Adrenal insufficiency can result from primary disorder of the adrenal gland or occurs secondarily due to deficiency in adrenocorticotropic hormone (ACTH) or corticotropin-releasing hormone (CRH). To prevent adrenal crisis, it is thus important to test the remaining function of the adrenal gland. Tests for the function of the hypothalamic-pituitary-adrenal (HPA) axis are also useful for examining localization of disease causing adrenal insufficiency. Generally, the insulin tolerance test (ITT) is useful for examining the HPA axis in both hypothalamic and pituitary diseases; however, ITT has a number of disadvantages. The growth hormone-releasing peptide (GHRP)-2 test may be a useful tool for diagnosing secondary adrenal insufficiency such as hypothalamic disorder and pituitary damage. In the present study, we examined the diagnostic usefulness of the GHRP-2 test as a substitute for ITT in hypopituitarism. We showed that patients with significant ACTH response to ITT also had significant response to the GHRP-2 test, while patients with no significant ACTH response to ITT also had no significant response to the GHRP-2 test. These data suggest that the GHRP-2 test may be a useful diagnostic tool for secondary adrenal insufficiency such as hypothalamic disorder and pituitary damage.
authors.affiliation: Department of Endocrinology and Metabolism, Hirosaki University Graduate School of Medicine, Aomori, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kageyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nigawara
authors.forename: Satoru
authors.initials: S
authors.lastname: Sakihara
authors.forename: Shinobu
authors.initials: S
authors.lastname: Takayasu
authors.forename: Ken
authors.initials: K
authors.lastname: Terui
authors.forename: Takako
authors.initials: T
authors.lastname: Moriyama
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Suda
mesh_terms: D000293:Adolescent; D000309:Adrenal Insufficiency / Q000175:diagnosis*; D000324:Adrenocorticotropic Hormone / Q000172:deficiency; D000328:Adult; D000368:Aged; D003346:Corticotropin-Releasing Hormone; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology*; D007328:Insulin; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000502:physiology*
chemical_list: D007328:Insulin; D009842:Oligopeptides; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; C091874:growth hormone-releasing peptide-2