PT-141 (Bremelanotide): Melanocortin Mechanism in Research
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PT-141 is a synthetic analog of α-MSH that acts on central melanocortin receptors. Review of its pharmacological profile for research on sexual function.
Chemical identity
PT-141 (also known as Bremelanotide) is a cyclic heptapeptide analog of α-MSH (α-melanocyte-stimulating hormone). Its mechanism differs from other agents investigated for sexual function because it acts in the central nervous system —not at the peripheral vascular level— via melanocortin receptors.
Sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Mechanism of action
PT-141 is a non-selective agonist of the melanocortin receptors, with principal affinity for:
- MC4R (melanocortin-4): central mediator of sexual behavior and satiety
- MC3R (melanocortin-3): energy regulation
- MC1R (melanocortin-1): dermal pigmentation
Activation of MC4R in specific hypothalamic nuclei (paraventricular) modulates central pathways related to the sexual response in animal models.
Differentiation vs. PDE5 inhibitors
| Característica | PT-141 | Inhibidores PDE5 |
|---|---|---|
| Sitio de acción | SNC (hipotálamo) | Vasculatura periférica |
| Home | 30-60 min | 30-60 min |
| Independencia de estímulo vascular | Sí | No |
| Aplicable a respuesta deseo | Sí | No |
Preclinical studies
| Modelo | Endpoint |
|---|---|
| Rata macho | Latencia de monta y erección |
| Rata hembra | Comportamiento de proceptividad |
| Modelo isquemia | Efecto neuroprotector de melanocortinas |
Reconstitution
Vial of 10 mg + 2 mL bacteriostatic water = 5 mg/mL Vial of 10 mg + 1 mL bacteriostatic water = 10 mg/mL
Half-life and frequency
Approximate plasma half-life: 2-4 hours In preclinical literature, administrations are performed on demand, not in chronic cycles.
Adverse effects in preclinical literature
Studies frequently report:
- Transient nausea (30-50% of subjects)
- Dermal hyperpigmentation with prolonged use (via MC1R)
- Transient increase in blood pressure
Required purity
- HPLC ≥99%
- Confirmation by mass spectrometry of the expected molecular mass (1025.18 Da)
- COA per batch
Stability
| Condición | Lyophilized | Reconstituted |
|---|---|---|
| -20°C | 24 months | 60 días |
| 2-8°C | 12 months | 28 days |
References
- Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstet Gynecol. 2019;134(5):899-908. doi:10.1097/AOG.0000000000003500. PMID 31599840. (human, phase 3 RCT)
- King SH, Mayorov AV, Balse-Srinivasan P, Hruby VJ, Vanderah TW, Wessells H. Melanocortin receptors, melanotropic peptides and penile erection. Curr Top Med Chem. 2007;7(11):1098-1106. PMID 17584130. (revisión)
- Wessells H, Gralnek D, Dorr R, Hruby VJ, Hadley ME, Levine N. Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology. 2000;56(4):641-646. doi:10.1016/S0090-4295(00)00680-4. PMID 11018622. (human)
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See also
Literature on the compounds cited
- Sobre PT-141 (Bremelanotida): Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. (Kingsberg SA, et al. · Obstet Gynecol · 2019) PMID 31599840.
- Sobre PT-141 (Bremelanotida): Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. (Simon JA, et al. · Obstet Gynecol · 2019) PMID 31599847.
- Sobre PT-141 (Bremelanotida): Safety Profile of Bremelanotide Across the Clinical Development Program. (Clayton AH, et al. · J Womens Health (Larchmt) · 2022) PMID 35147466.