Mutations in human urate transporter 1 gene in presecretory reabsorption defect type of familial renal hypouricemia.

To date, 11 loss of function mutations in the human urate transporter 1 (hURAT1) gene have been identified in subjects with idiopathic renal hypouricemia. In the present studies we investigated the clinical features and the mutations in the hURAT1 gene in seven families with presecretory reabsorption defect-type renal hypouricemia and in one family with the postsecretory reabsorption defect type. Twelve affected subjects and 26 family members were investigated.

cAMP inhibits cytokine-induced biosynthesis of tetrahydrobiopterin in human umbilical vein endothelial cells.

We studied the effects of cAMP on cytokine (interferon-gamma plus tumor necrosis factor-alpha)-induced stimulation of tetrahydrobiopterin (BH4) synthesis in human umbilical vein endothelial cells (HUVEC). The cytokine mixture caused a marked increase in the biosynthesis and release of BH4 by HUVEC. Dibutyryl-cAMP produced a dose-dependent inhibition of this cytokine-induced stimulation of synthesis and release of BH4 by these cells.

(6R)-5,6,7,8-tetrahydro-L-monapterin from Escherichia coli, a novel natural unconjugated tetrahydropterin.

The structure of the major tetrahydropterin in Escherichia coli was determined as (6R)-5,6,7,8-tetrahydro-L-monapterin, i. e. (6R)-2-amino-5,6,7,8-tetrahydro-6-[(1S,2S)-1,2,3-trihydroxypropyl]pteridin-4(3H)-one.