UniProt-P01241 — Somatotropin / Human Growth Hormone (GH1)

[DRAFT — authored 2026-04-19. UniProt entry web-verified via REST flat-file 2026-04-19.]

Entry

UniProt accession: P01241 (entry name SOMA_HUMAN)
Alt accessions: A6NEF6, Q14405, Q16631, Q5EB53, Q9HBZ1, Q9UMJ7, Q9UNL5
Protein name: Somatotropin (Growth hormone, GH)
Gene: GH1
Organism: Homo sapiens (Human)
Sequence length: 217 aa precursor (26-residue signal peptide + 191-aa mature hormone, residues 27-217)
Molecular weight: 24,847 Da (mature form ~22 kDa)
Origin: Anterior pituitary somatotrophs

Function Summary

Secreted by the anterior pituitary in response to hypothalamic GHRH (with GHRP/ghrelin co-stimulation and somatostatin inhibition). Binds the growth hormone receptor (GHR) on hepatocytes and peripheral tissues, triggering JAK2-STAT5 signaling and IGF-1 production.

Hepatic: stimulates IGF-1 synthesis and release (the principal downstream mediator of most GH effects)
Muscle/adipose: enhances differentiation and proliferation of myoblasts, amino-acid uptake, protein synthesis, and lipolysis
Bone: anabolic via IGF-1 and direct effects on chondrocytes and osteoblasts
Metabolism: counter-regulatory to insulin at supra-physiological concentrations (insulin resistance)
Circulatory forms: multiple oligomeric forms; can complex with growth-hormone binding protein (GHBP) or α-2-macroglobulin

Relevance to Module 5 Peptides

GH-axis peptides in Module 5 stimulate endogenous pituitary GH secretion rather than replacing GH directly:

Tesamorelin: GHRH analog (FDA-approved for HIV lipodystrophy); drives pulsatile GH release with preserved feedback loop
Sermorelin: GHRH(1-29) analog
CJC-1295 NO DAC / CJC-1295 W DAC: Modified GHRH analogs with extended half-life
Ipamorelin: Ghrelin-receptor (GHSR) agonist / GHRP — stimulates GH release through the ghrelin pathway
Hexarelin, GHRP-2, GHRP-6, MK-677: Additional GHS-receptor agonists
AOD-9604: GH-fragment (176-191); separate lipolytic mechanism, NOT a GH secretagogue

Recombinant human GH (somatropin — pharmaceutical form of P01241) is itself FDA-approved for various indications but is NOT a core Module 5 peptide (insurance/regulatory considerations distinct from the secretagogue class).

Cross-References to Vault Research Notes

UniProt-Q92847 – GHSR Ghrelin Receptor — ghrelin / GHS receptor (target of ipamorelin and GHS-family peptides)
Peptide profiles using GH-secretagogue mechanism: Tesamorelin, Sermorelin, CJC-1295 NO DAC, Ipamorelin

Orchestrator Notes

Primary mechanism reference for Lesson 5.5 (Tesamorelin + AOD-9604 + MOTS-C protocols) and Lesson 5.6 (Lean Mass Preservation with CJC/Ipamorelin).
Verified 2026-04-19 via UniProt REST flat-file API (https://rest.uniprot.org/uniprotkb/P01241.txt).