PT-141 (Bremelanotide) — PT-141 10mg

PT-141, known scientifically as Bremelanotide, is a synthetic heptapeptide and a potent analog of the endogenous peptide hormone alpha-melanocyte-stimulating hormone (α-MSH). Its chemical structure is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. PT-141 is notable in the research community as a key metabolite of Melanotan II, from which it was derived. Critically, it lacks the C-terminal amide group present in Melanotan II, a structural modification that significantly alters its receptor binding profile and subsequent biological activity investigated in laboratory settings.

This unique structural distinction makes PT-141 a highly selective ligand for specific melanocortin receptors. While α-MSH and Melanotan II are non-selective agonists across multiple melanocortin receptor subtypes, PT-141 exhibits primary agonism at the melanocortin-3 (MC3R) and melanocortin-4 receptors (MC4R), with substantially less affinity for the melanocortin-1 receptor (MC1R). This selectivity is of high interest to researchers, as MC1R is primarily responsible for stimulating melanin production (melanogenesis) in skin melanocytes. By minimizing MC1R activation, PT-141 allows for the isolated investigation of MC3R and MC4R-mediated pathways in the central nervous system without the confounding variable of significant pigmentary changes observed with less selective analogs.

Consequently, PT-141 has become an invaluable tool for neuroscientists, endocrinologists, and physiologists studying the intricate CNS pathways that govern complex behaviors. Its application in preclinical models enables the exploration of centrally mediated processes, including sexual arousal, appetite regulation, and metabolic homeostasis. As a research compound, PT-141 provides a precise mechanism for probing the functional roles of hypothalamic MC3R and MC4R signaling cascades. All products, including PT-141, are supplied by Nexa Peptides strictly for in vitro laboratory research and are not intended for human consumption. The insights gained from such studies contribute to a fundamental understanding of neuropeptide signaling in physiological regulation.

The mechanism of action for PT-141 (Bremelanotide) is centered on its function as a potent agonist at specific subtypes of the melanocortin receptor (MCR) family, particularly the melanocortin-3 receptor (MC3R) and melanocortin-4 receptor (MC4R). These receptors are G protein-coupled receptors (GPCRs) predominantly expressed in the central nervous system, including key regions of the hypothalamus such as the paraventricular nucleus (PVN) and the medial preoptic area (mPOA), which are integral to regulating energy homeostasis and sexual behavior.

Upon binding to MC3R and MC4R, PT-141 initiates a canonical GPCR signaling cascade. The peptide-receptor complex catalyzes the exchange of GDP for GTP on the associated Gs alpha subunit of the heterotrimeric G protein. This activation causes the Gs alpha subunit to dissociate and stimulate the membrane-bound enzyme adenylyl cyclase. Activated adenylyl cyclase then catalyzes the conversion of adenosine triphosphate (ATP) into the second messenger cyclic adenosine monophosphate (cAMP). This amplification step is a hallmark of GPCR signaling, allowing a small number of receptor activation events to generate a robust intracellular response.

The subsequent rise in intracellular cAMP levels leads to the activation of Protein Kinase A (PKA). PKA is a serine/threonine kinase that phosphorylates a multitude of downstream protein targets within the neuron. One of the most critical targets in this pathway is the cAMP response element-binding protein (CREB). Phosphorylated CREB translocates to the nucleus, where it binds to specific DNA sequences known as cAMP response elements (CREs) in the promoter regions of target genes, thereby modulating gene transcription. This cascade ultimately alters neuronal excitability, neurotransmitter release, and synaptic plasticity in the targeted brain circuits.

The molecular structure of PT-141, a cyclic heptapeptide with a molecular weight of 1025.2 g/mol, is optimized for stability and receptor affinity. The inclusion of a D-phenylalanine residue and the cyclic structure confer resistance to enzymatic degradation, prolonging its activity in research models. Importantly, the mechanism of PT-141 is distinct from that of peripherally acting agents. Its activity is centrally mediated, initiating signaling within the brain to modulate downstream physiological responses. This central action makes it a specific tool for researchers aiming to dissect the neural circuits governing sexual motivation and arousal, distinguishing these CNS-driven processes from peripheral vascular mechanics. All investigations using PT-141 are conducted in controlled laboratory environments for research purposes only.

PT-141 (Bremelanotide) is a specialized peptide utilized exclusively in preclinical research settings to investigate the neurobiological basis of sexual function, desire, and metabolic control. Its primary application is in the field of neuroscience, where it serves as a pharmacological tool to probe the role of central melanocortin pathways in regulating complex behaviors. In numerous in vivo animal models, typically involving rodents such as rats and mice, researchers have administered PT-141 to study its effects on centrally mediated sexual arousal. These studies often measure behavioral endpoints, such as lordosis behavior in female models or erectile responses in male models, to characterize the function of MC3R and MC4R activation within the hypothalamus and other relevant brain regions.

Another significant area of research involves the use of PT-141 in animal models designed to study hypoactive sexual desire disorder (HSDD). By activating melanocortin receptors in the brain, researchers can explore the neural circuits that underlie sexual motivation and receptivity. These investigations help to elucidate the intricate interplay of neuropeptides, hormones, and neurotransmitters in the regulation of libido, providing fundamental insights into the physiology of sexual desire. The central mechanism of PT-141 is particularly valuable in these studies, as it allows for the differentiation between central motivational states and peripheral physiological capabilities.

Beyond sexual function, PT-141 is also employed in metabolic research. The MC4R is a well-established and critical regulator of energy balance, food intake, and body weight. Studies in animal models utilize PT-141 to investigate how activation of this receptor influences appetite and energy expenditure. By observing changes in feeding behavior and metabolic parameters following PT-141 administration, scientists can further delineate the role of the central melanocortin system in metabolic homeostasis and its potential overlap with pathways regulating other motivated behaviors. These studies are crucial for understanding the complex hypothalamic integration of various physiological drives.

Furthermore, some research explores the broader effects of melanocortin agonism on the cardiovascular and autonomic nervous systems. Preclinical studies have examined how central MC4R activation by agents like PT-141 can influence parameters such as blood pressure and heart rate. This line of inquiry helps to map the connections between hypothalamic control centers and peripheral autonomic outflow. It is imperative to note that all these applications are strictly confined to non-human, laboratory-based research. The findings are intended to advance scientific knowledge and are not indicative of any approved clinical use. This product is for Research Use Only.