Ibutamoren Mesylate (MK-0677) is a potent, non-peptide Growth hormone secretagogue receptor (GHSR) agonist.

Following oral administration Ibutamoren Mesylate(MK0677) amplifies episodic GH release.?Mechanistically, it synergizes with growth hormone releasing hormone (GHRH) through a receptor and signal transduction pathway distinct from that of GHRH and is a functional antagonist of somatostatin (SRIF).?MK0677 also acts on the arcuate nucleus and appears to stimulate GHRH release.?By using 35S-MK0677, a new G-protein coupled receptor for MK0677 was characterized in the plasma membrane fraction of pituitary and hypothalamic tissue.?The receptor is present in very low abundance and couples to phospholipase C. Other ligands selective for this receptor also cause synchronization of well-defined pathways leading to GH release.?Repeated oral treatment of dogs once daily with MK0677 initiates amplified pulsatile GH release accompanied by increases in IGF-1 that are sustained.?The unique biological properties of MK0677 and other synthetic ligands that bind to the same receptor force us to predict that these ligands mimic a naturally occurring hormone that regulates pulsatile GH release[1].