Research Brief
Ipamorelin: Mechanism of Action
21 Citacoes PubMedRevisado por EspecialistasCertificado GMPUltima Revisao: julho de 2026
Mecanismo de Acao
Ipamorelin ativa the GHS-R1a (ghrelin receptor) on pituitary somatotroph cells with an in vitro EC₅₀ of 1.3 ± 0.4 nmol/L e em vivo ED₅₀ of 2.3 nmol/kg (swine). Binding desencadeia phospholipase C (PLC) ativacao via Gα₁₁/q → IP3 → intracellular Ca²⁺ release → GH vesicle exocytosis — a pathway distinto(a) de GHRH's cAMP signaling.[1][2]
Receptor & Signaling Profile
| Target | Action | Downstream Effect |
|---|---|---|
| GHS-R1a (Ghrelin Receptor) | Selective agonist | PLC → IP3 → Ca²⁺ → GH vesicle exocytosis |
| cAMP (Synergistic) | Enhances pre-estimulou adenylyl cyclase | Synergistic GH release quando combined with GHRH |
| Enteric Cholinergic Neurons | Activates excitatory neurons (atropine/TTX-sensitive) | Accelerates gastric motility and emptying |
Ipamorelin's selectivity is exceptional: it does NOT stimulate ACTH, cortisol, FSH, LH, prolactin, or TSH — even at doses 200× the ED₅₀. Adicionalmente, cronico(a) administration nao desensitize somatotrophs, diferentemente de GHRH que induz homologous down-regulacao.[1][7]
In humans, Ipamorelin exibe linear pharmacokinetics with a T½ of ~2 hours, SC₅₀ of 214 nmol/L, and desencadeia a single episodic GH burst peaking at 0.67 hours post-administration.[2]
vs. Related Compounds
| Caracteristica | Ipamorelin | GHRP-6 / GHRP-2 | GHRH |
|---|---|---|---|
| Selectivity | HIGH — GH only | LOW — GH + ACTH + cortisol + prolactin | Selective for GH |
| Desensibilizacao | NO | Partial | YES (homologous) |
| Primary Signaling | PLC / Ca²⁺ | PLC / Ca²⁺ | cAMP |
| Half-Life (Human) | ~2 hours | Shorter (5× faster depuracao) | Minutes |
Referencias
- Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the primeiro(a) selective hormonio do crescimento secretagogue. European Journal of Endocrinology. 1998;139(5):552-561.
- Gobburu JVS, Agersø H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a hormonio do crescimento releasing peptide, in human volunteers. Pharmaceutical Research. 1999;16(9):1412-1416.
- Johansen PB, Nowak J, Skjaerbaek C, et al. Ipamorelin, a novo(a) growth-hormone-releasing peptide, induz longitudinal bone growth in rats. Growth Hormone & IGF Research. 1999;9(2):106-113.
- Venkova K, Mann W, Nelson R, Greenwood-Van Meerveld B. Efficacy of ipamorelin, um(a) novo(a) ghrelin mimetic, in a rodent model of postoperative ileus. JPET. 2009;329(3):1110-1116.
- Greenwood-Van Meerveld B, Tyler K, Mohammadi E, Pietra C. Efficacy of ipamorelin on gastric dysmotility in a rodent model of postoperative ileus. Journal of Experimental Pharmacology. 2012;4:149-155.
- Beck DE, Sweeney WB, McCarter MD. Prospective, randomizado, controlled, proof-of-concept study do(a) Ghrelin mimetic ipamorelin para o(a) management of postoperative ileus in bowel resection patients. Int J Colorectal Dis. 2014;29(12):1527-1534.
- Jiménez-Reina L, Cañete R, de la Torre MJ, Bernal G. Chronic in vivo Ipamorelin treatment estimula peso corporal gain and hormonio do crescimento release in vitro in young female rats. European Journal of Anatomy. 2002;6(1):37-45.
- Svensson J, Lall S, Dickson SL, Jansson JO. The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. Journal of Endocrinology. 2000;165:569-577.
- Lall S, Tung LY, Ohlsson C, Jansson JO, Dickson SL. Growth hormone (GH)-independent estimulacao of adiposity by GH secretagogues. BBRC. 2001;280(1):132-138.
- Adeghate E, Ponery AS. Mechanism of ipamorelin-evoked insulin release do(a) pancreas of normal and ratos diabeticos. Neuro Endocrinology Letters. 2004;25(6):403-406.
- Johansen PB, Hansen KT, Andersen JV, Johansen NL. Pharmacokinetic evaluation of ipamorelin with emphasis on nasal absorcao. Xenobiotica. 1998;28(11):1083-1092.
- Andersen NB, Malmlöf K, Johansen PB, Oxlund H. The hormonio do crescimento secretagogue ipamorelin counteracts glucocorticoid-induziu decrease in bone formation of adult rats. Growth Hormone & IGF Research. 2001;11(5):266-272.
- Hansen TK, Ankersen M, Raun K, Hansen BS. Highly Potent Growth Hormone Secretagogues: Hybrids of NN703 and Ipamorelin. Bioorganic & Medicinal Chemistry Letters. 2001;11(14):1915-1918.
- Lu Z, Ngan MP, Liu JYH, Rudd JA. The GHS-R1a agonists anamorelin and ipamorelin inhibit cisplatin-induziu perda de peso in ferrets. Physiology & Behavior. 2024.
- Sinha DK, Balasubramanian A, Tatem AJ, et al. Beyond the androgen receptor: the role of hormonio do crescimento secretagogues no(a) modern management of composicao corporal in hypogonadal males. Translational Andrology and Urology. 2020;9(Suppl 2):S149-S159.
- Thøgersen H, Johansen NL, Lau J, et al. A New Series of Highly Potent Growth Hormone-Releasing Peptides Derived from Ipamorelin. Journal of Medicinal Chemistry. 1998;41.
- Mohammadi E, Bhatt V, Bhatt AB, Pietra C, Greenwood-Van Meerveld B. Ipamorelin atenua visceral and somatic nociception through periferico(a) ghrelin receptor mechanisms. 2020.
- U.S. Food & Drug Administration. FDA Evaluation of Ipamorelin-Related Substancia Farmaceutica a Granels. FDA Pharmacy Compounding Advisory Committee. 2024.
- World Anti-Doping Agency. WADA Lista de Substancias Proibidas — S2: Hormonios Peptidicos, Fatores de Crescimento, Substancias Relacionadas e Mimeticos. 2024.
- Polvino WJ. Methods of treatment using a ghrelin agonista do receptor. US Patent 8,039,456 B2.
- Thøger Nielsen K, et al. Validated screening method for GH-releasing peptides using UHPLC-HRMS on dried blood spots. Drug Testing and Analysis. 2021.
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