Ghrelin vs IGF-DES

Must be acylated at Ser3 (by GOAT enzyme) for GHSR-1a binding. Receptor activation in the pituitary stimulates GH release; hypothalamic action via NPY/AgRP neurons increases appetite and reduces energy expenditure.

An endogenous 28-amino acid peptide hormone produced primarily by gastric oxyntic cells. Functions as both the primary hunger signal and a potent GH secretagogue. The natural ligand for the growth hormone secretagogue receptor (GHSR-1a).

N-terminal truncation eliminates IGFBP binding, leaving nearly all circulating IGF-DES unbound and active. Results in substantially higher tissue IGF-1R activation versus native IGF-1 at equivalent doses. Activates PI3K/Akt/mTOR for muscle hypertrophy and satellite cell proliferation.

A truncated form of IGF-1 with the first 3 amino acids removed. Does not bind IGF binding proteins (IGFBPs), resulting in dramatically higher free active concentration at tissue level. Considered highly anabolic with limited systemic safety data in humans.