Concordant and discordant adrenocorticotropin (ACTH) responses induced by growth hormone-releasing peptide-2 (GHRP-2), corticotropin-releasing hormone (CRH) and insulin-induced hypoglycemia in patients with hypothalamopituitary disorders: evidence for direct ACTH releasing activity of GHRP-2.
The insulin-induced hypoglycemia test (insulin tolerance test: ITT) and corticotropin-releasing hormone (CRH) test are used to examine the activities of the hypothalamo-pituitary-adrenal (HPA) axis. Growth hormone-releasing peptide-2 (GHRP-2), a potent GH secretagogue, also stimulates adrenocorticotropin (ACTH) secretion. To evaluate the role of GHRP-2 in assessing the HPA axis, we examined 6 patients with various hypothalamo-pituitary disorders, and measured ACTH and cortisol responses during provocative tests (ITT, CRH, and GHRP-2 test). None of the 6 patients showed any significant ACTH or cortisol responses to ITT, but significant ACTH release was observed during CRH and GHRP-2 tests. These findings suggest GHRP-2 may directly stimulate ACTH secretion in patients with hypothalamo-pituitary disorders.
Kimura
Takashi
T
Department of Cardiovascular, Respiratory and Metabolic Medicine Graduate School of Medicine, Kagoshima University, Sakuragaoka, Kagoshima, Japan. kurokuma@m.kufm.kagoshima-u.ac.jp
Shimatsu
Akira
A
Arimura
Hiroshi
H
Mori
Hideki
H
Tokitou
Akinori
A
Fukudome
Michiyo
M
Nakazaki
Mitsuhiro
M
Tei
Chuwa
C
D000304:Adrenal Cortex Function Tests; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism*; D000328:Adult; D000368:Aged; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000139:chemically induced* / Q000378:metabolism; D007027:Hypothalamic Diseases / Q000097:blood / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000494:pharmacology*
D007328:Insulin; D009842:Oligopeptides; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; C091874:growth hormone-releasing peptide-2