MT-2

MT-2 functions as a synthetic agonist of melanocortin receptors. Its primary effect on skin pigmentation is mediated through activation of the melanocortin 1 receptor (MC1R) on melanocytes. Upon binding to the G-protein-coupled MC1R, MT-2 activates adenylyl cyclase, which catalyzes the conversion of ATP to cyclic adenosine monophosphate (cAMP). The resulting increase in intracellular cAMP activates Protein Kinase A (PKA), which then phosphorylates the cAMP response element-binding protein (CREB). Phosphorylated CREB translocates to the nucleus and initiates transcription of the Microphthalmia-associated transcription factor (MITF) gene—the master regulator of melanocyte development and function. MITF subsequently activates key melanogenic enzymes, including tyrosinase, tyrosinase-related protein 1 (TRP-1), and TRP-2. Beyond MC1R, MT-2's activation of MC3R and MC4R contributes to its effects on energy balance, appetite suppression, and sexual function.

• Pigmentation and Photoprotection: Investigated for its ability to induce melanogenesis (eumelanin production), with potential applications in photoprotection and dermatological disorders.
• Metabolic and Obesity Research: Employed in preclinical models to study appetite suppression, food intake reduction, and thermogenic responses.
• Sexual Function and Erectile Dysfunction: Studied for its dose-dependent induction of penile erection and reduction of latency to first erectile event. Its metabolite PT-141 (Bremelanotide) was subsequently developed for this indication.
• Neuroprotection and Nerve Regeneration: Investigated for neuroprotective qualities and promotion of peripheral nerve regeneration.
• Neuroendocrinology and Behavior: Utilized as a pharmacological tool to study melanocortin receptor signaling, social behavior, and stress responses.

CAS Number: 121062-08-6
Molecular Formula: C₅₀H₆₉N₁₅O₉
Molecular Weight: 1,024.15–1,024.18 g/mol
Sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ (lactam bridge: Asp²–Lys⁷)
Purity: ≥ 99% (batch-dependent; refer to Certificate of Analysis)
Form: White to off-white lyophilized powder
Storage: Lyophilized powder stable at ≤ -20°C, desiccated, and protected from light. Upon reconstitution, store at 2–4°C for up to 7 days; for long-term storage, keep below -18°C and avoid repeated freeze-thaw cycles.
Solubility: Soluble in sterile water (≥5 mg/mL) and DMSO; prepare working solutions per laboratory protocol