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The melanocortin system is an excellent example of how different receptor subtypes of the same family mediate different functions. Analogs of melanocyte-stimulating hormone act on melanocortin receptors (MC1R–MC5R):
- Melanotan-1 (afamelanotide): more selective for MC1R, the central receptor in melanogenesis (melanin production and skin pigmentation).
- Melanotan-2: a less selective agonist that activates several subtypes, which broadens its effect profile.
- PT-141 (bremelanotide): a derivative that acts preferentially on MC4R in the central nervous system, a pathway involved in sexual response; it has formal clinical development in desire disorders.
The pharmacological lesson is subtype selectivity: small sequence differences redirect the molecule from the skin (MC1R) to the CNS (MC4R), completely changing its field of research. GHK-Cu (Module 4) complements this dermal block from the matrix remodeling side.
Catalogue compounds mentioned in this lesson
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