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

Abstract

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; nZ19) with classical GHD in adult life and another (GH sufficient (GHS); nZ18) 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 group 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.European Journal of Endocrinology 155 91-99

The advantage of measuring spontaneous growth hormone (GH) secretion compared with the insulin tolerance test in the diagnosis of GH deficiency in young adults

“…In our study, the pattern of spontaneous nocturnal GH secretion appears to be crucial for the diagnosis of GHD in young adults, in accordance with a recent published study 22 . Conversely, the higher mean spontaneous GH secretion found in our young controls compared to that reported in healthy adults by Hoffman et al 12 .…”

“…21 In our study, the pattern of spontaneous nocturnal GH secretion appears to be crucial for the diagnosis of GHD in young adults, in accordance with a recent published study. 22 Conversely, the higher mean spontaneous GH secretion found in our young controls compared to that reported in healthy adults by Hoffman et al 12 could be explained by the subjects' age difference and pattern of spontaneous GH secretion, as well as by their higher BMI. 23 -25 In addition, 14 with structural hypothalamic-pituitary abnormalities and low spontaneous GH secretion had peak GH responses to the ITT above 5 µg/l, confirming that a cut-off peak GH of less than 5 µg/l following the ITT cannot identify all subjects with permanent GHD of childhood onset.…”

The arginine stimulation test: timing of peak is not a helpful parameter in the diagnosis of growth hormone deficiency

“…Indeed, the total percentage of typical ASTs (70.7%) in the current study was similar to the percent of typical GSTs (76%) and the highest average level of 12.56 ± 1.0 ng/mL for the AST (at 45 min) was similar to the 11.2 ± 0.5 ng/mL for the GST (at 120 min) (6). Also, physiologically, disordered patterns of secretion have been described as part of the growth hormone deficiency syndrome (9,10). Therefore, we expected to find that timing in the AST would be of similar importance and potential usefulness.…”

Diagnosis of adult GH deficiency

“…The large majority (more than 90%) of patients with childhood-onset multiple hypopituitarism show persistent severe GHD at retesting as adults. On the other hand, among patients who had been treated with rhGH for isolated GHD in childhood a lower percentage (varying between 30 and 70%) shows persistence of severe GHD at retesting in adulthood [5,15,22,39,52,65,73,82,98,102,103,110,112].…”