A Low Dose of Ghrelin Stimulates Growth Hormone (GH) Release Synergistically with GH-Releasing Hormone in Humans

The synergistic relationship between GH-releasing secretagogue (GHS) and GH-releasing hormone (GHRH) with respect to GH secretion is well known. In the present study, we report a similar relationship between GHRH and ghrelin, a recently identified endogenous ligand for the GHS receptor. In normal male adults, various doses of ghrelin were intravenously administered alone or together with 1.0 microg/kg GHRH. At small doses of 0.08 and 0.2...