Growth hormone (GH) secretion and pituitary size in children with short stature. Efficacy of GH therapy in GH-deficient children, depending on the pituitary size.

INTRODUCTION: Certain relationships between pituitary size and growth hormone (GH) secretion have previously been observed, however they are still a matter of controversy. Organic abnormalities of the hypothalamic-hypophyseal region are important for predicting growth response to GH therapy.

AIM: Evaluation of relations between GH secretion and the pituitary size in short children and estimation of the efficacy of GH therapy in children with GH deficiency (GHD).

PATIENTS AND METHODS: The analysis comprised 216 short children (159 boys). Two GH stimulation tests, as well as magnetic resonance image (MRI) examination, were performed in each patient. All the patients with GHD were treated with GH for, at least, one year.

RESULTS: Significant correlations were found between pituitary height and GH secretion (p < 0.05). Patients were classified into three (3) groups: 1) pituitary hypoplasia (HP) for height age; 2) HP for the chronological age but not for the height age; 3) normal pituitary size. Significant differences in GH secretion were observed among the groups (6.1+/-5.3 vs. 8.1+/-4.4 vs. 12.3+/-9.1 ng/mL, respectively). There was a negative correlation between GH peak and height gain during GH therapy (r = -0.34). The highest growth improvement was noticed in patients with HP for the height age.

CONCLUSIONS: Pituitary hypoplasia for the height age is related to more severe GH deficiency and the best response to GH therapy.