Abstract
The present study was designed to investigate the effect of α-melanocyte-stimulating hormone (α-MSH), nitric oxide (NO) and L-cysteine on melanin production and expression of related genes
MC1R, Tyr, Tyrp-1
and
Tyrp-2
in muzzle melanocytes of differently colored three native Hanwoo cattle. Muzzle samples were taken from black, brindle and brown Hanwoo and purified melanocytes were cultured with α-MSH, nitric oxide and L-cysteine at 100 nM, 50 µM and 0.07 mg/ml of media respectively. The amounts of total melanin, eumelanin and mRNA expression at
Tyr, Tyrp-1, Tyrp-2
and
MC1R
levels were quantified. α-MSH and nitric oxide significantly increased (p<0.05) the amount of total melanin in black and brindle whereas eumelanin production in brown Hanwoo muzzle melanocytes. On the contrary, L-cysteine greatly (p<0.05) depressed the eumelanin production in black color but increased in brown. Simultaneously, up regulation of
Tyr
by nitric oxide and α-MSH and down regulation of
Tyr, Tyrp-2
and
MC1R
genes by L-cysteine were observed in muzzle melanocytes of all three phenotypes. The results of this study revealed nitric oxide and α-MSH contribute hyper-pigmentation by enhancing eumelanogenesis whereas L-cysteine contributes to pheomelanin production in different colored Hanwoo muzzle melanocytes.