The influence of dexamethasone on growth hormone (GH). Response to GH-releasing hormone in normal men.

There is evidence that glucocorticoids may have a bimodal effect on growth hormone release in vitro and in vivo. To explore the influence of a single low dose administration of dexamethasone on the hypothalamic-pituitary-somatotropic system, 11 male healthy subjects received 50 micrograms synthetic human GHRH-44 amide as an i.v. bolus dose with and without pretreatment with orally administered 1 mg dexamethasone 9 hours prior to GHRH stimulation. Dexamethasone preparation did affect neither baseline levels of GH and IGF-I nor GHRH induced GH secretory patterns assessed by delta max and by the net area under the response curves. These results add to previous reports that corticosteroids may have different effects on GH secretory dynamics dependent on dose and duration of application.