Category: endocrine_axis
Hypothalamic GHRH stimulates pituitary GH release; somatostatin (SST) inhibits. GH acts on hepatocyte GHR → JAK2 → STAT5 → IGF-1 production (the main mediator of GH growth effects). Synthetic GHRH analogs (sermorelin, mod-grf-1-29, cjc-1295 — DAC-extended) pulse-stimulate endogenous GH. GHS-R agonists (ghrelin pathway — ghrp-2, ghrp-6, ipamorelin, hexarelin) are an orthogonal route to GH release via the stomach ghrelin receptor. Tesamorelin is a GHRH analog approved for HIV-associated lipodystrophy. mk-677 (ibutamoren) is an oral non-peptide GHS-R agonist. Direct GH replacement: somatropin (recombinant human GH) for GH deficiency. IGF-1 analogs: igf-1-lr3 (research only) + mecasermin (Increlex). ACE-031 inhibits myostatin (negative muscle-growth regulator). AOD-9604 is a GH fragment with claimed lipolytic activity (research-only). Acromegaly Rx: octreotide/lanreotide (SST analogs — see somatostatin pathway in END-6).