GH secretory pattern in young adults who discontinued GH treatment for GH deficiency and decreased longitudinal growth in childhood

Objective: Some adolescents who discontinue GH treatment due to GH deficiency (GHD) and short stature in childhood do not have classical GHD at retesting in adult life. It is unknown whether there is a neuroendocrine disturbance in the spontaneous pattern of GH release in these patients. Design/patients/methods: Thirty-seven adolescents, who had received treatment with GH due to impaired longitudinal growth, were included. The adolescents were divided into two groups; one (GHD; n = 19) with classical GHD in adult life and another (GH sufficient (GHS); n = 18) without classical adult GHD. One year after GH discontinuation, 24-h GH profiles were performed with blood sampling every 30 min. Sixteen matched healthy controls were also studied. All blood samples were analysed using an ultrasensitive GH assay and then, approximate entropy (ApEn) and deconvolution analysis were performed. Results: The GHD grou p had higher mean ApEn level than the healthy controls (P < 0.05). As measured by deconvolution analysis, they had lower basal GH secretion (P < 0.01), increased number of GH peaks (P < 0.001), but lower burst mass (P < 0.001), lower percentage pulsatile GH secretion (P < 0.001) and lower total GH secretion (P < 0.001), compared with control subjects. Adolescents in the GHS group had a pattern of 24-h GH release similar to that in healthy controls. Conclusion: Young adults with childhood-onset severe GHD have a high-frequency, low-amplitude GH secretion with decreased orderliness. The adolescents without classical GHD in adult life maintain a pattern of spontaneous GH release that is not statistically different from that in the healthy controls.