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
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.
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
↳ could be up-regulated by UV
③ β-amyloid precursor protein (APP) →
help melanosome transport
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