Vitamin C transport and SVCT1 transporter expression in chick renal proximal tubule cells in culture.

摘要: Abstract The characteristics of vitamin C (ascorbic acid, ASC) transport were studied in polarized cultured monolayers the chick ( Gallus gallus ) renal proximal tubule Ussing chambers. Under voltage clamp conditions, responded to apical addition ASC a dose-dependent manner, with positive short circuit currents I SC ), ranging from 3 μA/cm 2 at 5 μM maximal response 27 μA/cm 200 μM, and half-maximal 40 μM. There was no effect basolateral ASC, indicating process. oxidized form dehydroascorbic acid had negligible effects. completely eliminated Na + ion replacement, also by bilateral reduction bath Cl − , 137 2.6 mM. significant inhibition responses 30 μM flavanoid quercetin (50 μM) 100 μM 4,4′-diisothiocyanostilbene-2,2′-disulfonic (DIDS) 5-ethylisopropylamiloride (EIPA), blockers anion exchangers sodium-proton exchangers, respectively. inhibition, however, chloride channel blocker 5-nitro-2(3-phenylpropylamino)benzoic (NPPB). Phorbol 12-myristate 13 acetate (PMA), phorbol ester activator protein kinase C, caused 37% decrease ASC. Chicken-specific primers an EST homolog human transporter SVCT1 (SLC23A1) designed used probe expression these cells. RT-PCR analysis demonstrated presence chicken both cells freshly isolated fragments. These data indicate electrogenic, sodium-dependent (SVCT1) tubule. Vitamin conservation kidney is likely be especially critical birds, due high plasma glucose levels resulting reactive oxygen species.