Tetrahydrobiopterin-dependent preservation of nitric oxide–mediated endothelial function in diabetes by targeted transgenic GTP–cyclohydrolase I overexpression
J. Clin. Invest. Nicholas J. Alp, et al. 112:725 doi:10.1172/JCI17786 [Go to this article.]

Figure 6
Effect of diabetes on GTPCH expression and aortic biopterins. (a) Total GTPCH mRNA levels in aorta from diabetic or control GCH-Tg mice and WT littermates were determined by quantitative RT-PCR and plotted on a log scale. Total GTPCH mRNA levels were increased fivefold in GCH-Tg as compared with WT mice (*P < 0.05, n = 3), but diabetes did not affect GTPCH expression in either group. (b) Total biopterin and BH4 levels in aorta from diabetic or GCH-Tg transgenic mice and WT littermates. There was a threefold increase in total biopterin levels in GCH-Tg aortas as compared with WT. Diabetes had no effect on total biopterin levels as compared with control in either group. However, in WT diabetic aortas, BH4 was almost undetectable, and BH4 levels in diabetic GCH-Tg aortas were significantly reduced as compared with control (*P < 0.05, n = 4–6).