High concentration of ghrelin in children with growth hormone deficiency and neurosecretory dysfunction.

BACKGROUND: The role of endogenous ghrelin in the growth process of children is unclear. The aim of the present study was to assess ghrelin concentrations in children with growth hormone deficiency (GHD), neurosecretory dysfunction (NSD) and idiopathic short stature (ISS) in comparison to healthy controls.

MATERIAL: One hundred and forty seven children (61 girls and 86 boys), aged 3.7-16.8 years (mean±SD: 10.7±3.44 years) with short stature (below -2.0 SD) were qualified into the study. In each child, fasting ghrelin and insulin-like growth factor type I (IGF-I) concentrations were measured and growth hormone (GH) secretion was assessed after falling asleep and during two GH-stimulating tests. According to maximal GH concentrations, children were qualified into GHD, NSD and ISS group. Additionally, depending on biological development, the children were divided on younger and older subgroups. The control group consisted of 19 healthy children with normal height and body mass.

RESULTS: Ghrelin concentrations in GHD (1847.5±1444.3 pg/mL) and NSD (1809.3±983.5 pg/mL) were significantly higher than in ISS (1218.1±646.8 pg/mL) and in Controls (924.9±318.4 pg/mL). A comparison of ghrelin concentrations in older and younger children within the same diagnostic group, showed statistically higher ghrelin levels in younger than in older children (except of NSD group, in which the difference reached the border of statistical significance).

CONCLUSIONS: Ghrelin concentration is elevated in GHD and NSD children. Independently of GH and IGF-I secretion disorders type, ghrelin concentrations decrease with the children' age. The higher concentration of ghrelin in ISS than in Controls suggests the presence of GH-independent factors increasing ghrelin secretion by X/A cells in the gastric oxyntic mucosa.