GH secretion is modulated by a complex interplay between two hypothalamic factors, GHRH (growth hormone-releasing hormone) and somatostatin (SRIF). More recently, a third physiological mechanism mediated by GHS (growth hormone secretagogues) and its endogenous counterpart, ghrelin, has been discovered. Glucocorticoids (GCs) influence GH secretion acting at several levels, although the mechanisms involved in its multiple actions are not fully elucidated. Moreover, these steroids have stimulatory or inhibitory effects on GH release depending on the experimental model, duration of exposure, dose, type and route of administration, among other factors. Although controversial, acute GCs administration enhances GH secretion in man. However, when given for longer periods (months or years), it inhibits GH release. The effects of these steroids on IGF-1 and IGFBPs are quite controversial.
GH; Glucocorticoids; GHRH; GHRP-6; Ghrelin
