Understanding the PT-141 Peptide

by | Aug 31, 2022 | Research

Because it previously treated female Hypoactive Sexual Desire Disorder (HSDD) in phase IIb of human clinical trials, PT-141 peptide is also known as Bremelanotide and Female Viagra. A melanocortin, PT-141, binds to melanocortin 4 and 1 receptors (MC-4R and MC-1R).

In 2009, scientists tested a hypothesis on PT-141 peptide for its ability to treat acute hemorrhage. Notably, PT-141 is a derivative of Melanotan 2, a synthetic melanocortin (MT-2).

 

How Does PT-141 Peptide Work?

PT-141, a cyclic heptapeptide analog, activates melanocortin. Melanocortin activation is specific to the central nervous system, inducing erections and improving sexual functions.

The peptide acts on the central nervous system, making it an alternative ED medication for men with high blood pressure or heart problems that prevent them from taking PDE5 inhibitors[1].

Regardless of dose, PT-141 takes longer to exert its effects than PDE5 inhibitors. Higher doses ranging from 10 to 20mg do not produce erections that last as long as the PDE5 inhibitor.

PT-141, on the other hand, has a variety of mechanisms of action and functions; however, the following are its functions and how it works.

 

How PT-141 Peptide Impacts Sexual Arousal and its Mechanism of Action

  • PT-141 influences and stimulates the MC-4R, causing sexual arousal in the central nervous system and modulating sexual behaviors. Clinical studies show that PT-141 peptide binds to MC-4R antagonistically, inducing sexual arousal and increasing copulation in both males and females[2]. The mechanism of action of PT-141 differs from that of Viagra, allowing the peptide to treat sexual arousal disorders in males and females caused by factors other than decreased blood flow to the genitals.
  • PT-141 peptide clinical trials in men with Erectile Dysfunction (ED) who do not respond to sildenafil (Viagra) reveal that roughly one-third have an erection sufficient for sexual intercourse (administration is via nasal spray)[3]. The efficacy of PT-141, on the other hand, is dose-dependent, implying that the peptide can treat ED when sildenafil cannot and may also provide solutions to the underlying causes of hypoactive sexual desire.
  • Despite evidence that the peptide increased various gratifying sexual events per month and significantly reduced female sexual distress scores with no adverse effects, PT-141 was withdrawn from clinical trials in women with HSDD before FDA approval. Despite the positive results, female sexual dysfunction (FSD) specialists were disappointed because the peptide was not advanced. According to the professionals, the primary factors impeding peptide approval are a lack of established endpoints for FSD trials and sociocultural biases against women’s sexual health.
  • Scientists believe that PT-141 peptide when combined with other peptides for treating sexual dysfunction, can overcome early setbacks and jump-start psychological treatment modalities.
  • In response to the discontinuation of earlier trials in 2017, phase II reconnects launched difficulties with subcutaneous injections of PT-141 for FSD. Scientists have created Rekynda, the most recent version of the PT-141 peptide that can treat both male and female dysfunction.

 

How PT-141 Peptide Impacts Infections?

MC-1R has anti-inflammatory and antifungal properties in mice models with a specific fungal infection. This is critical because standard antifungals limit the mechanism of action and have adverse and treatment-limiting effects in some patients. However, an alternative treatment for fungal infections can reduce mortality and morbidity, particularly in patients with compromised immune systems.

 

The Functions of PT-141 Peptide in Hemorrhage

  • PT-141 treats hemorrhagic shocks by binding to the MC-1R and MC-4R, reducing ischemia and protecting tissues from inadequate blood supply following hypovolemic (hemorrhagic) shock
  • The intravenous administration of PT-141 does not impact adverse effects.

 

The Impact of PT-141 Peptide on Cancer

The MC-1R is a potent stimulator of DNA repair pathways that can be used to treat and prevent cancer. Clinical studies show that people with the MC-1R variant are more likely to develop squamous and basal cell carcinoma. The peptide, however, can reverse the problems associated with this variant and treat and prevent these cancers by modifying Pt-141.

 

The Adverse Effects of PT-141 Peptide

PT-141 peptide administration subcutaneously resulted in severe adverse effects via nasal spray during the study[4]. However, there were few side effects associated with nasal administration of the peptide. As a result, the adverse effects or symptoms are as follows:

  • Nausea
  • Dysgeusia
  • Headaches
  • Vomiting
  • Fever
  • Somnolence
  • Flushing
  • Back pain
  • Diaphoresis
  • Fatigue
  • Muscle cramps
  • Dark urine
  • Blurred vision
  • Pulsatile tinnitus
  • Jaundice

Patients who were given high doses of PT-141 vomited after 6-15 hours. This effect indicates a toxicity level that may pose a risk with long-term use.

 

Conclusion

PT-141 peptide is a well-known drug for the treatment of sexual dysfunction. Despite this, robust clinical studies of PT-141 go beyond hemorrhage and sexual dysfunction, such as its effects on obesity. PT-141 allows for the investigation of the cause of obesity and the development of an intervention strategy. Much research indicates that PT-141 peptide is vital in inflammation, pain, kidney pathology, and infection spread. To summarize, PT-141 is a research peptide/drug intended for educational and scientific purposes, not for human use or consumption.

 

References


  1. Kim S, Cho MC, Cho SY, Chung H, Rajasekaran MR. Novel Emerging Therapies for Erectile Dysfunction. World J Mens Health. 2021 Jan;39(1):48-64. doi: 10.5534/wjmh.200007. Epub 2020 Mar 16. PMID: 32202086; PMCID: PMC7752520.
  2. Molinoff PB, Shadiack AM, Earle D, Diamond LE, Quon CY. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Ann N Y Acad Sci. 2003 Jun;994:96-102. doi: 10.1111/j.1749-6632.2003.tb03167.x. PMID: 12851303.
  3. Diamond LE, Earle DC, Rosen RC, Willett MS, Molinoff PB. Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction. Int J Impot Res. 2004 Feb;16(1):51-9. doi: 10.1038/sj.ijir.3901139. PMID: 14963471.
  4. Rosen RC, Diamond LE, Earle DC, Shadiack AM, Molinoff PB. Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra. Int J Impot Res. 2004 Apr;16(2):135-42. doi: 10.1038/sj.ijir.3901200. PMID: 14999221.

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