Melanotan One is a selective agonist of the MC1R (melanocortin 1 receptor).* As an analogue of the naturally occurring melanocortin alpha-MSH, Melanotan One delivers a photoprotective response through the MC1 receptor.* Binding to melanocyte cells, it begins a series of actions and reactions that result in the melanocyte favoring the production of eumelanin (black/brown) over pheomelanin (red/yellow).
A breakthrough in understanding the function of eumelanin and pheomelanin was demonstrated in recent years. Early in life, our genetics determine our constitutional quantities of the protective (eumelanin) vs the damaging pigment (pheomelanin).
Melanocytes creating eumelanin, thereby increasing pigmentation of the skin and thus providing photoprotection is the therapeutic benefit intended from the administration of Melanotan One.
Melanin is the natural substance that gives color (pigment) to hair, skin, and the iris.
Tyrosinase is responsible for the first step in melanin production.* Tyronsinase is involved in melanogenesis resulting in heightened levels of the enzyme in the melanocyte.* The level of enzymes melanocytes have dictate whether the cell will create eumelanin (photoprotective black/brown pigment).
Regulation of eumelanin/pheomelanin synthesis and visible pigmentation in melanocytes by ligands of the melanocortin 1 receptor.
2008
Abstract
The production of melanin in the hair and skin is tightly regulated by the melanocortin 1 receptor (MC1R) whose activation is controlled by two secreted ligands, alpha-melanocyte stimulating hormone (alphaMSH) and agouti signal protein (ASP). As melanin is extremely stable, lasting years in biological tissues, the mechanism underlying the relatively rapid decrease in visible pigmentation elicited by ASP is of obvious interest. In this study, the effects of ASP and alphaMSH on the regulation of melanin synthesis and on visible pigmentation were assessed in normal murine melanocytes and were compared with the quick depigmenting effect of the tyrosinase inhibitor, phenylthiourea (PTU). alphaMSH increased pheomelanin levels prior to increasing eumelanin content over 4 days of treatment. Conversely, ASP switched off the pigment synthesis pathway, reducing eu- and pheo-melanin synthesis within 1 day of treatment that was proportional to the decrease in tyrosinase protein level and activity. These results demonstrate that the visible depigmentation of melanocytes induced by ASP does not require the degradation of existing melanin but rather is due to the dilution of existing melanin by melanocyte turnover, which emphasizes the importance of pigment distribution to visible color.
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Levels of eumelanin (left) and pheomelanin (right) in melanocytes and media after treatment with ASP, PTU or ?MSH