title: Growth hormone releasing hexapeptide-6 (GHRP-6) test in the diagnosis of GH-deficiency.
abstract: Pituitary GH reserve can be assessed by substances that act directly at the somatotroph, such as GHRH, or by a variety of metabolic and neuropharmacological tests acting at the hypothalamic level, such as hypoglycemia, clonidine or L-Dopa. In order to evaluate GHRP-6 as a test of pituitary GH reserve, we studied GH responses of i.v. administered GHRP-6 in a group of short-statured children, as well as in a group of adults diagnosed with growth hormone deficiency (GHD) by conventional GH testing. Although we found that the GH response to GHRP-6 was lower in patients with GHD than in normal children, on an individual basis a considerable degree of overlap was observed between the two groups. In contrast, we found an almost complete blockade of GH response to either GHRP-6 or GHRH plus GHRP-6 in patients with pituitary stalk transection, suggesting that this could be a cost-effective test for the diagnosis of this condition. A similar finding was also obtained in GH response to the combined administration of GHRH plus GHRP-6 in patients with GHD of adult onset; this test may well prove valuable in the diagnosis of this clinical entity.
authors.affiliation: Department of Pediatrics, University of Santiago de Compostela, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Pombo
authors.forename: A
authors.initials: A
authors.lastname: Leal-Cerro
authors.forename: J
authors.initials: J
authors.lastname: Barreiro
authors.forename: A
authors.initials: A
authors.lastname: Peñalva
authors.forename: R
authors.initials: R
authors.lastname: Peino
authors.forename: F
authors.initials: F
authors.lastname: Mallo
authors.forename: C
authors.initials: C
authors.lastname: Dieguez
authors.forename: F F
authors.initials: FF
authors.lastname: Casanueva
mesh_terms: D002648:Child; D006130:Growth Disorders / Q000175:diagnosis* / Q000209:etiology; D013007:Growth Hormone-Releasing Hormone; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency*; D006801:Humans; D009842:Oligopeptides
chemical_list: D009842:Oligopeptides; D019382:Human Growth Hormone; C041048:growth hormone releasing hexapeptide; D013007:Growth Hormone-Releasing Hormone