Endocrine Abstracts

Introduction: GH deficiency (GHD) is a clinical disorder characterized by pathological short stature in the child, altered body composition, impaired psychological well-being and reduced quality of life. These alterations are almost always reversible after recombinant human GH (rhGH) administration, which is currently the only accepted treatment for the subjects with GHD. Secretory dysfunction is confirmed when GH peak does not reach the established cut-off in at least two different stimulus tests performed in two different days. When tests response is considered adequate, the short stature is considered idiopathic and no GH replacement therapy is advised.

Objective: To determine the effect of GH provocative tests on growth rate in children without GH deficiency.

Design and Methods: Children of both gender with pathological short stature (h< 3°percentile) and/or annual growth rate <-2 SDS but with normal response to two GH provocative tests, were selected. Diagnosed endocrinopathies, other organ dysfunction, autoimmune diseases, genetic syndrome or current drug therapies were excluded. Height, mid-parental height, body weight, and body mass index were registered. The height and annual growth rate were converted to percentiles and Standard Deviation Score using reference ranges standardized for age and sex and were recorded pre and post stimulus tests and during subsequent follow-up over time. GH provocative tests employed arginine or clonidine as secretagogues.

Results: Twenty-one children of both genders were enrolled. Heights were measured at test time and at a mean time prior and after the tests of 209 days and 192 days respectively. Children displayed a 5-fold increase of their annual growth rate. The mean growth rate of children pre- and post-tests were -4.3 SDS and +2.0 respectively (P<0.0001). In 9 children the height was measured two times after the tests at an average time of 228 days and 887 days. All children displayed a stimulated growth also in the second time interval after the tests, with a decremental in some.

Conclusions: Two sequential somatotropic axis provocative tests increase the growth rate in non-GHD children with pathological short stature and that this effect persists for several months.