Interaction of Human Organic Anion Transporters 2 and 4 with Organic Anion Transport Inhibitors

2002 ◽  
Vol 301 (3) ◽  
pp. 797-802 ◽  
Author(s):  
Atsushi Enomoto ◽  
Michio Takeda ◽  
Minoru Shimoda ◽  
Shinichi Narikawa ◽  
Yukari Kobayashi ◽  
...  
2001 ◽  
Vol 419 (2-3) ◽  
pp. 113-120 ◽  
Author(s):  
Michio Takeda ◽  
Shinichi Narikawa ◽  
Makoto Hosoyamada ◽  
Seok Ho Cha ◽  
Takashi Sekine ◽  
...  

2003 ◽  
Vol 285 (5) ◽  
pp. E1103-E1109 ◽  
Author(s):  
Fanfan Zhou ◽  
Kunihiko Tanaka ◽  
Michael J. Soares ◽  
Guofeng You

Transporters within the placenta play a crucial role in the distribution of nutrients and xenobiotics across the maternal-fetal interface. An organic anion transport system was identified on the apical membrane of the rat placenta cell line HRP-1, a model for the placenta barrier. The apical uptake of 3H-labeled organic anion estrone sulfate in HRP-1 cells was saturable ( Km = 4.67 μM), temperature and Na+ dependent, Li+ tolerant, and pH sensitive. The substrate specificity of the transport system includes various steroid sulfates, such as β-estradiol 3,17-disulfate, 17β-estradiol 3-sulfate, and dehydroepiandrosterone 3-sulfate (DHEAS) but does not include taurocholate, p-aminohippuric acid (PAH), and tetraethylammonium. Preincubation of HRP-1 cells with 8-bromo-cAMP (a cAMP analog) and forskolin (an adenylyl cyclase activator) acutely stimulated the apical transport activity. This stimulation was further enhanced in the presence of IBMX (a phosphodiesterase inhibitor). Together these data show that the apical membrane of HRP-1 cells expresses an organic anion transport system that is regulated by cellular cAMP levels. This transport system appears to be different from the known taurocholate-transporting organic anion-transporting polypeptides and PAH-transporting organic anion transporters, both of which also mediate the transport of estrone sulfate and DHEAS.


2015 ◽  
Vol 59 (12) ◽  
pp. 7666-7670 ◽  
Author(s):  
Tomohiro Nabekura ◽  
Tatsuya Kawasaki ◽  
Yuki Kamiya ◽  
Yuichi Uwai

ABSTRACTPlacental drug transfer is important for achieving better pharmacotherapy in pregnant women and in fetuses. In the present study, we examined the effects of anti-hepatitis C virus (HCV) and anti-HIV drugs on organic anion transport in human placental BeWo cells. The cellular uptake of two fluorescence organic anions, 8-(2-[fluoresceinyl]aminoethylthio)adenosine-3′,5′-cyclic monophosphate (8-FcAMP) and fluorescein, was temperature and concentration dependent. The Michaelis constant (Km) and the maximum uptake rate (Vmax) for 8-FcAMP transport in BeWo cells were estimated to be 6.45 ± 0.75 μM and 25.55 ± 5.93 pmol/mg protein/10 min, respectively. TheKmandVmaxvalues for fluorescein uptake were estimated to be 31.2 ± 11.8 μM and 510.9 ± 90.6 pmol/mg protein/10 min, respectively. Several known substrates of organic anion transporters in human placenta, including atorvastatin, glibenclamide, estrone-3-sulfate, and rifampin, inhibited cellular uptake of 8-FcAMP and fluorescein in BeWo cells. Transport of 8-FcAMP and fluorescein was inhibited by the antiviral drugs boceprevir, telaprevir, elvitegravir, and maraviroc. These findings suggest that some antiviral drugs are sufficiently potent to influence placental drug transfer and cause drug-drug interactions.


2016 ◽  
Vol 468 (11-12) ◽  
pp. 1909-1918 ◽  
Author(s):  
Birgitta C. Burckhardt ◽  
Maja Henjakovic ◽  
Yohannes Hagos ◽  
Gerhard Burckhardt

1994 ◽  
Vol 299 (3) ◽  
pp. 665-670 ◽  
Author(s):  
G Fricker ◽  
V Dubost ◽  
K Finsterwald ◽  
J L Boyer

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.


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