Endocrine and metabolic
Ghrelin receptor signalling
Activation of the growth hormone secretagogue receptor type 1a can stimulate pituitary growth hormone release and may also influence appetite, gastrointestinal function and neuroendocrine signalling.
Biological pathway
GHS-R1a agonism → Gq-linked intracellular signalling in hypothalamic and pituitary cells → growth hormone secretion, with ligand-specific effects on appetite and other hormones.
Evidence summary
Human pharmacology supports growth hormone release after several synthetic secretagogues, although clinical outcome evidence is limited and molecule-specific.
Limitations
Acute hormone responses do not establish improvements in body composition, recovery or long-term health. Some agonists also affect appetite, ACTH, cortisol or prolactin.