Tetrahydrobiopterin and Endothelial Nitric Oxide Synthase Uncoupling

Tetrahydrobiopterin and endothelial nitric oxide synthase uncoupling.

Tetrahydrobiopterin and Endothelial Nitric Oxide Synthase Uncoupling To the Editor: Gao et al1 reported that oral administration of folate, the tetrahydrobiopterin (H4B) precursor, attenuated endothelial NO synthase (eNOS) uncoupling in abdominal aortic aneurysm. The beneficial effects of H4B supplementation in endothelial dysfunction are beyond dispute, but in vivo demonstration of eNOS (un)co...

Dexamethasone, tetrahydrobiopterin and uncoupling of endothelial nitric oxide synthase

OBJECTIVE To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase (eNOS). METHODS & RESULTS A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopterin (BH4). Treatment of human EA.hy 926 endothelial cells with dexamethasone decreased mRNA and protein expression of both BH4-synthesizing enzymes: GTP cyclohydrolase I and dihydro...

Tetrahydrobiopterin and endothelial nitric oxide synthase activity.

Interactions of peroxynitrite, tetrahydrobiopterin, ascorbic acid, and thiols: implications for uncoupling endothelial nitric-oxide synthase.

Tetrahydrobiopterin (BH4) serves as a critical co-factor for the endothelial nitric-oxide synthase (eNOS). A deficiency of BH4 results in eNOS uncoupling, which is associated with increased superoxide and decreased NO* production. BH4 has been suggested to be a target for oxidation by peroxynitrite (ONOO-), and ascorbate has been shown to preserve BH4 levels and enhance endothelial NO* producti...

Tetrahydrobiopterin: important endothelial mediator independent of endothelial nitric oxide synthase.

Tetrahydrobiopterin (BH4), an essential cofactor for diverse cellular processes, is present in almost every cell or tissue of higher organisms. BH4 has well-defined functions in terms of enzymatic activities (BH4 is a crucial cofactor for the aromatic amino acid hydroxylases and all isoforms of nitric oxide synthase [NOS]) but has other less-defined functions in cells. BH4 is a growth or prolif...