GHRP-2 Test Offers Safer Alternative for Diagnosing Pituitary Hormone Deficiency

Hypopituitarism is a complex condition where the pituitary gland fails to produce sufficient amounts of one or more hormones, often including Growth Hormone (GH). The current gold standard for diagnosing GH deficiency is the Insulin Tolerance Test (ITT), which involves inducing hypoglycemia (low blood sugar) to stimulate GH release. However, the ITT carries significant risks, including seizures and cardiovascular events, making it unsuitable for some patients. This study aimed to evaluate the diagnostic accuracy and safety of the Growth Hormone-Releasing Peptide-2 (GHRP-2) test as a less invasive and safer alternative to the ITT for diagnosing GH deficiency in hypopituitarism.

The study revealed that the GHRP-2 test demonstrated high diagnostic accuracy compared to the ITT. Peak GH responses to GHRP-2 correlated strongly with those observed during the ITT (r = 0.88, p<0.001). Using a GH cut-off of 3 µg/L, the GHRP-2 test showed a sensitivity of 92% and a specificity of 85% for diagnosing GH deficiency. The GHRP-2 test induced significantly fewer adverse events (5%) compared to the ITT (43%), which frequently caused symptomatic hypoglycemia requiring intervention. Furthermore, the mean peak GH levels after GHRP-2 administration were 15.2 ± 3.1 µg/L in healthy controls versus 2.8 ± 0.9 µg/L in GH-deficient patients (p<0.001). The GHRP-2 test also proved to be significantly more comfortable for patients, with 95% reporting mild or no discomfort, compared to only 20% for the ITT.