The Growth Hormone Response to Hexarelin in Patients with Different Hypothalamic-Pituitary Abnormalities

We evaluated the GH-releasing effect of hexarelin (Hex; 2 μg/kg, iv) and GHRH (1 μg/kg, iv) in 18 patients (11 males and 7 females, aged 2.5–20.4 yr) with GH deficiency (GHD) whose hypothalamic pituitary abnormalities had been previously characterized by dynamic magnetic resonance imaging (MRI). Ten patients had isolated GHD, and 8 had multiple pituitary hormone deficiency. All patients were receiving appropriate hormone replacement therapy. Twenty-four prepubertal short normal children (11 boys and 13 girls, aged 5.9–13 yr, body weight within ±10% of ideal weight) served as controls. MRI studies revealed an ectopic posterior pituitary at the infundibular recess in all patients. A residual vascular component of the pituitary stalk was visualized in 8 patients with isolated GHD (group 1), whereas MRI showed the absence of the pituitary stalk (vascular and neural components) in the remaining 10 patients (group 2), of whom 8 had multiple pituitary hormone deficiency and 2 had isolated GHD. In the short norma...