Fig 1.
CV based on the constructed electrode modified with mixed SAM (HS-C6-Fc:HS-C6-OH = 1:3).
Current change based on UA concentrations was measured in CV. UA concentration was changed by 0.1 μg/mL. Insert: Current change in amperometric measurement at 0.4 V. Addition of UA is indicated by arrows.
Fig 2.
Excretion rate of UA in the intestinal closed loop.
Calculated excretion rate of UA in the intestine of rats subjected to sham, administration of serum UA-lowering drugs (benzbromarone, febuxostat, and topiroxostat), or Nx (n = 4–6). Crossbar in each group shows the median. Significant differences between the sham group and other groups are indicated as * (p<0.05), ** (p<0.01), and *** (p<0.005).
Fig 3.
Relative mRNA expression of UA transporters in the intestine.
mRNA expression of a) Oat1, b) Oat3, c) Mrp4, and d) Abcg2 in the intestine of rats subjected to sham, Nx, or treated with serum UA-lowering drugs (benzbromarone, febuxostat, and topiroxostat) (n = 4–6). mRNA levels were normalized to Gapdh. Crossbar in each group shows the median.
Fig 4.
Proposed model for the action of UA-lowering drugs on intestinal UA transporters.
Based on the results of this study, as well as previous reports, we suggest the expressed transporters Oat1, Oat3, Mrp4, and ABCG2 to be related to urate transport in the intestine. ABCG2 was inhibited by UA-lowering drugs used in this study.