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Comparison of pituitary-adrenal responsiveness between insulin tolerance test and growth hormone-releasing peptide-2 test : A pilot study

Kano-Wakakuri, Toshiko; Sugihara, Hitoshi; Sudo, Mariko; Nagao, Mototsugu LU ; Harada, Taro; Ishizaki, Akira; Nakajima, Yasushi; Tanimura, Kyouko; Okajima, Fumitaka and Tamura, Hideki, et al. (2010) In Peptides 31(4). p.657-661
Abstract

Insulin tolerance test (ITT) is the gold standard for assessing the hypothalamic-pituitary-adrenal (HPA) function. GH-releasing peptide (GHRP)-2, which has a strong GH-stimulating activity, is useful for diagnosing GH deficiency as well as ITT. Additionally, GHRP-2 is also known to activate HPA axis. There have been no comparative studies of pituitary-adrenal responsiveness between GHRP-2 test and ITT in patients with hypothalamic/pituitary disease. To assess whether GHRP-2 test could be an alternative to ITT for diagnosing HPA axis failure, both ITT and GHRP-2 test were performed in 15 patients suspected of hypopituitarism. A 100 μg dose of GHRP-2 was administered intravenously and plasma ACTH and serum cortisol concentrations were... (More)

Insulin tolerance test (ITT) is the gold standard for assessing the hypothalamic-pituitary-adrenal (HPA) function. GH-releasing peptide (GHRP)-2, which has a strong GH-stimulating activity, is useful for diagnosing GH deficiency as well as ITT. Additionally, GHRP-2 is also known to activate HPA axis. There have been no comparative studies of pituitary-adrenal responsiveness between GHRP-2 test and ITT in patients with hypothalamic/pituitary disease. To assess whether GHRP-2 test could be an alternative to ITT for diagnosing HPA axis failure, both ITT and GHRP-2 test were performed in 15 patients suspected of hypopituitarism. A 100 μg dose of GHRP-2 was administered intravenously and plasma ACTH and serum cortisol concentrations were measured. In ITT, a peak cortisol value over 18 μg/dl is considered normal. Nine patients were diagnosed as HPA axis failure by ITT. Their median peak cortisol in GHRP-2 test was 11.4 μg/ml. In 6 patients diagnosed as normal HPA axis status by ITT, their median peak cortisol in response to GHRP-2 test was 21.4 μg/dl, significantly higher (p = 0.0032) than seen in patients diagnosed as HPA axis failure. There was a strong correlation between the peak cortisol in GHRP-2 test and ITT (r = 0.817; p < 0.0001). When the cut-off value for the peak cortisol in GHRP-2 test was set to 13-14 μg/dl for diagnosing HPA axis failure, the specificity and sensitivity were 100% and 88.9%, respectively. Although further studies that include normal subjects are needed, these preliminary results suggest the possibility that GHRP-2 test may be an alternative to ITT for assessing HPA axis function.

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publishing date
type
Contribution to journal
publication status
published
keywords
GHRP-2, HPA axis, Insulin tolerance test
in
Peptides
volume
31
issue
4
pages
5 pages
publisher
Elsevier
external identifiers
  • scopus:77649234516
ISSN
0196-9781
DOI
10.1016/j.peptides.2009.12.023
language
English
LU publication?
no
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775bbdd6-49ac-4260-a17d-9b3da508ddc1
date added to LUP
2017-08-23 20:06:26
date last changed
2018-05-29 10:26:53
@article{775bbdd6-49ac-4260-a17d-9b3da508ddc1,
  abstract     = {<p>Insulin tolerance test (ITT) is the gold standard for assessing the hypothalamic-pituitary-adrenal (HPA) function. GH-releasing peptide (GHRP)-2, which has a strong GH-stimulating activity, is useful for diagnosing GH deficiency as well as ITT. Additionally, GHRP-2 is also known to activate HPA axis. There have been no comparative studies of pituitary-adrenal responsiveness between GHRP-2 test and ITT in patients with hypothalamic/pituitary disease. To assess whether GHRP-2 test could be an alternative to ITT for diagnosing HPA axis failure, both ITT and GHRP-2 test were performed in 15 patients suspected of hypopituitarism. A 100 μg dose of GHRP-2 was administered intravenously and plasma ACTH and serum cortisol concentrations were measured. In ITT, a peak cortisol value over 18 μg/dl is considered normal. Nine patients were diagnosed as HPA axis failure by ITT. Their median peak cortisol in GHRP-2 test was 11.4 μg/ml. In 6 patients diagnosed as normal HPA axis status by ITT, their median peak cortisol in response to GHRP-2 test was 21.4 μg/dl, significantly higher (p = 0.0032) than seen in patients diagnosed as HPA axis failure. There was a strong correlation between the peak cortisol in GHRP-2 test and ITT (r = 0.817; p &lt; 0.0001). When the cut-off value for the peak cortisol in GHRP-2 test was set to 13-14 μg/dl for diagnosing HPA axis failure, the specificity and sensitivity were 100% and 88.9%, respectively. Although further studies that include normal subjects are needed, these preliminary results suggest the possibility that GHRP-2 test may be an alternative to ITT for assessing HPA axis function.</p>},
  author       = {Kano-Wakakuri, Toshiko and Sugihara, Hitoshi and Sudo, Mariko and Nagao, Mototsugu and Harada, Taro and Ishizaki, Akira and Nakajima, Yasushi and Tanimura, Kyouko and Okajima, Fumitaka and Tamura, Hideki and Ishii, Shinya and Shibasaki, Tamotsu and Oikawa, Shinichi},
  issn         = {0196-9781},
  keyword      = {GHRP-2,HPA axis,Insulin tolerance test},
  language     = {eng},
  number       = {4},
  pages        = {657--661},
  publisher    = {Elsevier},
  series       = {Peptides},
  title        = {Comparison of pituitary-adrenal responsiveness between insulin tolerance test and growth hormone-releasing peptide-2 test : A pilot study},
  url          = {http://dx.doi.org/10.1016/j.peptides.2009.12.023},
  volume       = {31},
  year         = {2010},
}