Effects of sodium arsenite on mRNA expression of GTP cyclohydrolase and 6-pyruvoyl-tetrahydropterin synthase in chang liver cells.

Objective To study the effects of sodium arsenite on the mRNA expression of GTP cyclohydrolase (GTPCH) and 6-pyruvoyl-tetrahydropterin synthase (PTPS) in Chang liver cells. Methods Human Chang liver cells were cultured with sodium arsenite at doses of 0, 50, 200 and 400 μmol/L for 12 hours. Cell viability was tested by MTT assay, and the expression of mRNA of GTPCH and PTPS was detected by RT-PCR. Results Cell viability in 50 μmol/L group was almost the same as that in control, while the viability in the other two groups were significantly lower than that in control. All of the mRNA expression levels in the three groups were significantly lower than that in control with dose-dependent manner. Conclusion The down-regulated expression of GTPCH and PTPS, the main enzymes of the synthesis of BH4, induced by sodium arsenite exposure may be related with arsenic related skin depigmentation.