Growth deficiency with high circulating growth hormone levels: the insulin stimulation test in 39 children.

Thirty nine patients with abnormal high basal hGH levels were selected and analysed as a part of a retrospective study of the results of 1,500 insulin stimulation tests (IST), applied in children and adolescents with growth deficiency. Their height, weight, and bone age were lower than their corresponding chronological age. Both in girls and in boys groups, responders and nonresponders subgroups were detected as judging by the results of the secretagogue action of insulin on hGH. The hGH basal levels were 43.88 +/- 18.27 microU/ml (X +/- SD) in boys (no = 22) and 56.61 +/- 35.21 microU/ml in girls (no = 17). It is to be noted that the hGH nonresponder group had deeper hypoglycemia at 30 minutes post-insulin injection than the responder group: 53.6 +/- 13.0 mg/100 ml (X +/- SD) vs 66.0 +/- 11.5 mg/100 ml respectively (p less than 0.01). Two siblings, a girl and a boy, had the highest basal and stimulated hGH, either during the IST or starvation. One of them, the boy, during the starvation test, had a paradoxical fall of about two orders of magnitude of the serum hGH 4 hr after basal sample collection. These two siblings are similar to the familial Laron type dwarfism. The possible mechanisms of growth deficiency in children with constant high but variable hGH values are discussed, as well as the aspects concerning the therapeutic ways to improve their linear growth.