Do short children secrete insufficient growth hormone?
The 24-hour integrated concentration of growth hormone from 46 children of normal stature was compared with that of 90 short children. Nineteen of the short children had classic growth hormone deficiency by standard pharmacologic growth hormone stimulation tests. Seventy-one children had normal growth hormone responses to stimulation. The mean integrated concentration of growth hormone for children with normal stature (6.6 +/- 1.9 ng/mL) was greater than the mean value for those with normal stimulated growth hormone (3.8 +/- 2.3 ng/mL) and greater than the mean value for those with growth hormone deficiency (1.6 +/- 0.6 ng/mL); differences between groups were all statistically significant (P less than .0001). Forty-five percent of children with normal stimulated growth hormone responses had integrated concentration of growth hormone within the range of values for the group with growth hormone deficiency; this finding may provide the explanation for their poor growth. Thus, patients with normal growth hormone responses have a spectrum of spontaneous growth hormone secretion ranging from normal to impaired. Recent reports indicate that children with normal growth hormone responses who have very low integrated concentration of growth hormone may have the potential to improve their growth with growth hormone therapy. Therefore, use of the integrated concentration of growth hormone may be a more effective method than standard pharmacologic stimulation tests for determining which short children are potentially able to respond to growth hormone therapy.