Growth hormone neurosecretory dysfunction. A treatable cause of short stature.

Pulsatile growth hormone (GH) secretion was assessed in a subgroup of short children to determine whether they had GH secretory abnormalities, and these results were compared with those of normal and GH-deficient children. This subgroup of children was defined as having GH neurosecretory dysfunction and met the following criteria: height, less than first percentile; growth velocity, 4 cm/yr or less; bone age, two or more years behind chronological age, normal findings from provocative GH tests (peak, greater than or equal to 10 ng/mL), low somatomedin-C level, and abnormal 24-hour GH secretory patterns. When compared with controls, both children with GH neurosecretory dysfunction and GH-deficient patients had a significant decrease in parameters relating to the total GH secretion during the 24-hour period. As with GH-deficient children, the group with GH neurosecretory dysfunction more than doubled their growth velocity after replacement therapy with exogenous human GH during the first year of treatment. As a result of these detailed studies on pulsatile GH secretion, we suggest that there is a spectrum of GH secretory abnormalities from absolute deficiency to an intermittent irregularity in GH secretion.