In most cases PT 141 is now referred to as bremelanotide. This peptide was developed by Palatin Technologies, as a means of addressing female sexual dysfunction in animals through research indicates that this peptide may also be effective in addressing reperfusion and hemorrhagic shock following injuries. PT 141 is designed to activate melanocortin receptors, specifically MC1R and MC4R, as a means of limiting ischemia and reducing moderate inflammation in the animal’s tissues.
PT 141 was originally tested using intranasal administration in animals, but for some time this practice was banned because it was found that this application method caused a severe spike in blood pressure in test subjects. As of 2012 safer delivery methods have been developed so researchers may apply this peptide via inhalation or injection as necessary for their research.
Evaluating the Safety of PT-141
PT 141 was evaluated following intranasal administration in male animal test subjects when compared to the commonly used sexual behavior, correcting drug Viagra.
• The peptide was checked for effectiveness in treating erectile dysfunction in otherwise healthy test subjects without the use of sexual stimulation in responsive ED animals.
• Healthy test subject saw an improvement in erectile dysfunction symptoms that were dependent on the administration of the chemicals.
• Studies showed that PT 141 created a statistically significant improvement in symptoms when compared to the placebo group, particularly in administrations over 7mg. The initial erection was seen approximately 30 minutes after the application of the peptide. No maximum tolerated administration was identified, though.
• Test subjects were reported to experience flushing and nausea in both studies, but vital signs, ECGs, laboratory tests and physical exams did not report any significant changes.
Based on the potential to improve erectogenic conditions and its apparent high tolerance in test subjects, PT 141 may have promise in further evaluation, for addressing symptoms of erectile dysfunction in males.
Acting as an Antagonist for Sexual Dysfunction
PT 141 acts as an antagonist to melanocortin receptors within the central nervous system which may prove useful in correcting sexual dysfunction.
• Rats and nonhuman primates were exposed to PT 141 which led to penile erections. Systematically applying this peptide activated the neurons in the hypothalamus in rats which caused an increase in c-Fos.
• Neurons in nearby regions of the central nervous system took up pseudorabies viruses which were injected into the corpus cavernosum of the penis of male rats.
Administering PT 141 to male test subjects with erectile dysfunction caused a dose dependent, but rapid increase in erectile activities, suggesting that this peptide could be used to treat such conditions in humans with more research and development. This is, however, hasn’t been confirmed yet.
Palatin works to develop PT-141
PT-14 was a nasal spray that was designed to research the effects of this peptide on female sexual dysfunction and erectile dysfunction in males.
As of 2004 successful trials in male and female test subjects were developed, with additional testing scheduled for 2005. However, a significant amount of side effects exhibited in animal test subjects caused a ban on this research, which was lifted for researchers in 2008. Human testing or dosing is still not considered safe by the FDA.
PT 141 was developed by altering melanotan 2, though this peptide does not cause tanning of the skin the way the original chemical does. Research is still underway to determine the proper method of altering melanotan 2, as current versions of PT 141 tend to cause unpredictable side effects, particularly in male animal test subjects.
Given the spontaneous nature of the peptide, PT 141 is not yet approved for use or research on human candidates, even when being compared to chemicals such as Viagra that are commonly prescribed.