Effects of HPA axis-related hormones on melanin synthesis in vitro.

A: Measurement of melanin contents in normal human epidermal melanocytes (NHEMs) after treatment with 50 nM α-MSH or 1 µM DEX for 72 h. D: Measurement of melanin contents in B16F10 cells after treatment with 50 nM α-MSH or 1 µM DEX for 72 h. B–C: The mRNA expression levels of MITF and TYR in NHEMs after treatment with 50 nM α-MSH or 1 µM DEX for 24 h. E–F: The mRNA expression levels of MITF and TYR in B16F10 cells after treatment with 50 nM α-MSH or 1 µM DEX for 24 h. The expression levels of each gene were normalized against β-Actin or GAPDH then calculated as fold change using the comparative 2-ΔΔCT method. Data are combined from three separate experiments and showed in mean ± SEM, and the data were analyzed by one-way ANOVA with Tukey's post hoc test. * P, ** P, *** P, compared with control; &&P, compared with α-MSH.