When corticotroph deficiency, hypogonadotropic hypogonadism, and thyroid function were added to the model (model 2), the peak GH response to GHRP-2 (β = −0.342; 95% CI, −0.537 to −0.148; standardized β = −0.377) was also a significant variable. This evidence concerns the gene GH1 and hypogonadotropic hypogonadism.