Admin on Jan th, 2019

Skin color
A.    Cause by "melanocyte"
 ↳ produced melanosome which has melanin, then transfer to SC layer.
      ※    Skin color is dependent on how many melanosomes is on the SC layer, not by the numbers.
 ↳ In all mankind, the quantity of melanosome is the same
     ↳ depend on ① the activity of melanosome
                              ② the interaction between SC and melanosome
A. Eumelanin – in skin
    Pheomelanin – in hair
B. Tyrosinase – control the synthesis of melanin
     effect by - ① thymidine dinucleotide
                          ② melanocyte – stimulating hormone
                          ③ b FGF
                          ④ endothelin
                          ⑤ protein kinase C
                          ⑥ Cyclic adenosine monophosphate (cAMP)
                          ⑦ protein kinase A pathway
                          ⑧ prostaglandins D2, E2, F2
                          ⑨ Tumor necrosis factor (TNF-α)
                          ⑩ Interleukins (IL-1α, IL-1β, IL-6)
                          ⑪ Vitamin D
                               ⇒ They all synthesis melanin.
Melanosome Transport
A. ① Two pathway -
                phagocytosis ⇒ by macrophage → to Dermis 
                endocytosis ⇒ by keratinocyte → to Epidermis
    ② PAR-2 receptor (protease-activated receptor 2)
       ↳ is a G-protein-coupled receptor
           ↳be activated by serine protease ⇒   increase keratinocyte melanosome
                                             endocytosis melanosome
       ↳ could be up-regulated by UV
    ③ β-amyloid precursor protein (APP)   →
                                                                                  help melanosome transport 
        KGF/FGF-7                                                →
    ④ Soybean trypsin inhibitor (STI)          →
                                                                                  Inhibit melanosome transport
          Bowman–Birk inhibitor (BBI)             →
Melanin and Melanosome Distribution
A. Dark skin, melanosome size larger but much more scattered.
    White skin, melanosome size smaller but much more concentrated.
     ※    If melanosome > 0.35 μm, cannot concentrated.
     ※    The best anti-pigmentation products can only help your skin color back to your
             baby-born color.