PT-141 (Bremelanotide): Melanocortin Receptor Research and Sexual Function Models
Research Use Only. This article is for scientific and educational reference only. All products are sold for research purposes and are not intended for human or animal consumption.
Introduction
PT-141, also known as bremelanotide, is a synthetic cyclic heptapeptide and melanocortin receptor agonist derived from Melanotan II (MT-II). With the molecular formula C50H68N14O10 and a molecular weight of approximately 1025.18 Daltons, PT-141 has been the subject of extensive preclinical and clinical research for its role in modulating sexual arousal pathways through central nervous system mechanisms. Unlike phosphodiesterase type 5 (PDE5) inhibitors such as sildenafil, PT-141 acts centrally rather than through peripheral vascular mechanisms, representing a distinct pharmacological approach in sexual function research.Molecular Structure & Properties
PT-141 is a cyclic peptide with the amino acid sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. The cyclization between the aspartate and lysine residues, along with the incorporation of D-phenylalanine and norleucine, confers metabolic stability compared to linear ฮฑ-MSH analogs. PT-141 has high affinity for melanocortin receptor subtypes MC3R and MC4R, which are expressed in brain regions associated with sexual behavior, including the hypothalamus and limbic system [1].Mechanism of Action
PT-141's research-relevant mechanism centers on central melanocortin receptor activation:- MC4R agonism: Activation of MC4R in the paraventricular nucleus (PVN) of the hypothalamus has been associated with pro-erectile and pro-arousal signaling in rodent models, mediated through oxytocin and dopamine pathway interactions [2] - MC3R agonism: MC3R activation contributes to the modulation of feeding behavior and energy homeostasis, providing a secondary research dimension beyond sexual function - Dopaminergic interaction: PT-141's effects on sexual motivation in animal models appear to involve dopaminergic pathways in the mesolimbic system, distinct from the purely vascular mechanism of PDE5 inhibitors [3] - Nitric oxide independence: Unlike PDE5 inhibitors, PT-141's pro-erectile effects in animal models are observed even in the absence of nitric oxide synthase activity, suggesting a CNS-primary mechanism [4]
Research Applications
Sexual Dysfunction Models
PT-141 has been studied in both male and female sexual dysfunction models. In rodent studies, systemic administration of PT-141 has been shown to increase mount frequency, intromission frequency, and ejaculation latency in male rats, and to increase solicitation behaviors in female rats โ standard behavioral endpoints in sexual function research [5].Hypoactive Sexual Desire Research
The compound has been studied as a research tool in models of hypoactive sexual desire disorder (HSDD). Clinical research culminated in FDA approval of bremelanotide (Vyleesi) for HSDD in premenopausal women in 2019, making PT-141 one of the few peptides with a direct clinical translation pathway.Melanocortin System Research
Beyond sexual function, PT-141 serves as a valuable pharmacological tool for studying the broader melanocortin system, including its roles in energy homeostasis, inflammation, and cardiovascular regulation. Its selectivity profile (MC3R/MC4R over MC1R/MC5R) makes it useful for dissecting receptor subtype-specific effects.This article is intended for scientific and educational reference within a laboratory research context only. All products sold by Pure Pharm Peptides are for research use only and are not intended for human or animal consumption.
References
- Shadiack, A.M., et al. (2007). Melanocortins in the treatment of male and female sexual dysfunction. Current Topics in Medicinal Chemistry, 7(11), 1137โ1144.
- Giuliano, F., et al. (2010). Neurophysiology of erection and ejaculation. Journal of Sexual Medicine, 7(Suppl 6), 310โ315.
- Pfaus, J.G., et al. (2004). The melanocortin system mediates the ability of a dopamine D1 receptor agonist to facilitate sexual behavior in the female rat. Neuroscience, 125(4), 1027โ1034.
- Wessells, H., et al. (2000). Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology, 56(4), 641โ646.
- Molinoff, P.B., et al. (2003). PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Annals of the New York Academy of Sciences, 994, 96โ102.
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