The study shows that giving the peptide GHRP‑2 can trigger the same ACTH (adrenal‑stimulating hormone) response as the traditional insulin tolerance test (ITT) in people with pituitary problems. If the body reacts to GHRP‑2, it likely has a functional adrenal axis; if not, it probably doesn’t. This means GHRP‑2 could be used as a safer, simpler way to check adrenal health instead of the risky ITT.

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.