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A comparison of low‐dose ACTH, glucagon stimulation and insulin tolerance test in patients with pituitary disorders
Author(s) -
Simsek Y.,
Karaca Z.,
Tanriverdi F.,
Unluhizarci K.,
Selcuklu A.,
Kelestimur F.
Publication year - 2015
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.12528
Subject(s) - insulin tolerance test , medicine , endocrinology , pituitary disorder , context (archaeology) , acth stimulation test , stimulation , adrenocorticotropic hormone , adrenal insufficiency , glucagon , insulin , hydrocortisone , hormone , insulin resistance , biology , insulin sensitivity , paleontology
Summary Context Diagnosis of secondary adrenal insufficiency and GH deficiency requires evaluation by dynamic stimulation tests in most cases. Although insulin tolerance test ( ITT ) is accepted as the gold‐standard test for the evaluation of both hypothalamo‐pituitary‐adrenal ( HPA ) and ( GH )‐ IGF ‐1 axes, the test is cumbersome. In clinical practice, low‐dose adrenocorticotrophic hormone (ACTH) stimulation test is a sensitive, safe and easily applicable alternative to ITT . Although it takes more time, glucagon stimulation test ( GST ) is also a good alternative to ITT and can evaluate both axes. Objective The primary aim of this study was to compare the ITT , low‐dose ACTH and GST s in the evaluation of HPA and GH ‐ IGF ‐1 axes in patients with pituitary disorders and to evaluate the repeatability of all three tests. Design ITT , low‐dose ACTH and GST s were performed in all 129 patients, and the tests were repeated in 66 of these patients. Setting Erciyes University Medical School, Department of Endocrinology. Patients or Other Participants One hundred and twenty‐nine adult patients (76 women, 53 men) with pituitary disorder were included in the study. Main Outcome Measure(s) The cortisol and GH responses of patients to dynamic tests. Results Peak cortisol levels obtained during ITT were significantly lower than the values obtained during both low‐dose ACTH and GST s. Peak cortisol levels obtained during the GST were lower than those found during the low dose ACTH stimulation test. Peak GH responses were found to be higher in GST than in ITT . All three tests had good reproducibility. Conclusions Any of 3 tests can be used in the evaluation of the HPA axis and either GST or the ITT can be used in the evaluation of the GH ‐ IGF ‐1 axis but cut‐off levels for the insufficiency of HPA or GH ‐ IGF ‐1 axis should be individualized for each test.