Adrenal Function in GHD Children

The relationship between the growth hormone (GH)-insulin like growth factor (IGF)-I system and the hypothalamic-pituitary-adrenal (HPA) axis is complex and not univocal. Both a stimulatory and neutral effect of IGF-I on HPA axis has been demonstrated in in vitro models and in healthy subjects, respectively. The effect of GH on the 11beta-hydroxysteroid dehydrogenases (11beta-HSD) isozymes is always to be considered in patients affected by GHD both at diagnosis and during GH treatment. Indeed, in peripheral tissues, corticosteroid hormone action is partially determined by the activity of 11beta-HSD, two isozymes of which interconvert hormonally active cortisol and inactive cortisone. 11beta-HSD2 inactivates cortisol to cortisone in the kidney, whilst 11beta-HSD1 performs the reverse reaction activating cortisol from cortisone in the liver and adipose tissue.

For these reasons, many data are available about the evaluation of adrenal function in patients affeceted byGHD, but most of them come from patients with organic GHD or adult patients, while few and discordant data are available on pediatric GHD patients. We aimed to evaluate, through insulin tolerance test, the adrenal function in about 30 children with overt diagnosis of idiopathic GHD both at baseline and after 6 and 12 months of GH treatment.

• growth hormone (Drug): Children with a diagnosis of GHD will practice GH replacement therapy in line with normal clinical practice and international guidelines. Controls will be evaluated just at baseline.

Primary outcomes

• Evaluation of adrenal function in GHD children at baseline and in control group [baseline]: We will evaluate through insulin tolerance test the response of serum cortisol levels in GHD children at diagnosis (before start of GH therapy) and in controls subjects
• Change in adrenal function in GHD children during GH therapy [6 and 12 months]: We will evaluate through insulin tolerance test the response of serum cortisol levels in GHD children after 6 and 12 months of GH therapy

Sex: All, ages: 5 Years to 12 Years, accepts healthy volunteers

Inclusion Criteria:

* prepubertal children with overt idiopathic growth hormone deficiency

Exclusion Criteria:

* Children with organic growth hormone deficiency or under treatment with glucocorticoids