PT-141

PT-141 Peptide

Bremelanotide, which is also commonly known by PT-141, is a cyclic synthetic peptide composed of seven amino acids.⁽¹⁾ PT-141 synthetic peptide appears to be agonistic to melanocortin receptors, which is similar to the natural hormone alpha-MSH.⁽²⁾ It is a by-product of the metabolism of another synthetic analog called melanotan II. Initial studies suggested that melanocortin hormones may regulate various physiological functions. When test animals were presented with the isolated hormone, it was reported to present elevated reproductive functions, which is one of the primary areas of research currently being conducted on PT-141 peptide.

Overview

Studies have suggested that PT-141 shows agonistic properties towards melanocortin receptors, namely MC3R and MC4R, which may result in elevated reactions in the central nervous system. MC3R, which appears to be primarily expressed in the brain, especially within the hypothalamus, might play a role in energy homeostasis. It has been hypothesized by research teams examining melanocortin receptor activity, that MC3R may potentially modulate the actions of other melanocortin receptors in this area. Moreover, MC3R might influence feeding behavior, possibly impacting appetite and food intake, and is thought to be involved in various metabolic processes, including the potential regulation of glucose and lipid metabolism.⁽³⁾ On the other hand, MC4R is believed to be essential in appetite control. When activated in the brain, it is considered to contribute to appetite regulation. MC4R is also posited to have a role in energy expenditure, with its activation possibly leading to an increase in energy output, which could contribute to weight reduction. This receptor has also been tentatively linked to reproductive function, especially in the potential regulation of the function of penile tissues and overall reproductive behavior.⁽⁴⁾ In publically available study, it was suggested by researchers that following binding with MC3R and MC4R receptors, the peptide appeared to lead to the activation of the neurons found in the hypothalamus, leading to apparently increased immunoreactivity.²⁽⁾ Neurons in the surrounding region of the central nervous system may also be stimulated as they intake the chemicals which then reportedly lead to sexual arousal in murine models.

PT-141 Chemical Makeup

Molecular formula: C₅₀H₆₈N₁₄O₁₀
Molecular weight: 1025.18 g/mol
Other Known Titles: Bremelanotide

Research and Clinical Studies

PT-141 Peptide Initial Studies

This early 2000 study was conducted to understand the potential of PT-141 peptide in murine models. The murine models were used as the subject in this study to determine how the peptide may impact their sexual behavior.⁽⁵⁾ After presentation, it was reported that the female rats appeared to exhibit elevated sexual desire without any increase/decrease in the sexual pace, lumbar lordosis, or any other sexually-related behaviors. After analysis, it was suggested by the researchers that the peptide did not directly impact a generalized motor activation, instead it may have potential selective pharmacological impact that may stimulate the central nervous system, mainly the melanocortin receptor activities, which might result in elevated sexual arousal. More specifically, the researchers commented that “ The ability of PT-141 to enhance solicitation in two distinctive testing environments indicates that the effect is selective and stable, and suggests that central melanocortin systems are part of the neurochemical network that evokes appetitive sexual behavior in female rats.”⁽⁵⁾