Cyclic Adenosine Monophosphate Stimulates Melanogenesis in In Vitro Melanocytes from Skins of Taihe Silky Fowls

Abstract: This study was conducted to investigate the effect of cyclic adenosine monophosphate (cAMP) on melanin synthesis in skin melanocytes of Taihe silky fowls. The skin melanocytes of Taihe silky fowls were cultured in vitro with cAMP at a concentration of 0， 1×10–5， 1×10–4， 1×10–3 mol/L or pretreated with cAMP inhibitor (Rp-cAMPS) or adenylate cyclase (AC) inhibitor NKY80 prior to the addition of cAMP， and then the tyrosinase activity and melanin contents were determined. cAMP at various concentrations tested in the present study significantly increased TYR activity in silky fowl skin melanocytes with the highest tyrosinase activity in the 1×10–4 mol/L cAMP-treated cells (P<0.01). cAMP supplemented at all concentrations used in the present study stimulated pigmentation in skin melanocytes with different extents. Melanin content in 1×10–5 mol/L or 1×10–4 mol/L cAMP-treated cells were higher than that in control without cAMP supplementation (P<0.05 or P<0.01). However， pretreatment with Rp-cAMPS significantly inhibited the stimulatory effects of cAMP (1×10–4 mol/L) on tyrosinase activity (P<0.01) and melanin synthesis in skin melanocytes (P<0.05). Moreover， both pretreatments with Rp-cAMPS or AC inhibitor NKY80 significantly inhibited the stimulatory effects of α-melanocyte stimulating hormone (α-MSH) (2.5 μg/mL) on tyrosinase activity， cAMP formation and melanin synthesis in skin melanocytes of Taihe silky fowls (P<0.05 or P<0.01). In conclusion， cAMP， as the second messenger or downstream signal molecule in α-MSH-MC1R (melanocortin 1 receptor) signaling pathway， plays crucial role in melanogenesis， the tyrosinase activity and melanin content in skin melanocytes of Taihe silky fowls increase with the increasement of cAMP concentration at the suitable range.

CSTR: 32200.14.cjcb.2018.08.0014