Human growth hormone therapy of non-growth hormone deficient children.

With biosynthetically derived human growth hormone (hGH) available in large quantities, attempts will be made to promote growth in short children who do not fulfill the 'classical' criteria for growth hormone deficiency (GHD). By these criteria, GHD is excluded if hGH levels to pharmacological stimuli exceed a definite level. Several studies have shown that a variety of short children, who are not growth hormone deficient by these criteria, will demonstrate an increased growth rate with hGH treatment. A subpopulation of children with clinical features of GHD, delayed bone age and low somatomedin levels, have low levels of spontaneously secreted growth hormone or 'bioinactive' growth hormone. These children increase their growth rates to substitution doses of hGH. In other children whose growth disorder is not likely to be caused by a disorder in the growth hormone-somatomedin axis, growth increments are occasionally seen on higher hGH doses. Future long-term studies--carefully considering the ethics of such approaches--will have to evaluate the relationships between hGH dose and both metabolic and growth responses and side effects in children with short stature in order to define more specifically further target groups of short children who will benefit from hGH therapy.