estrone-sulfate and dioscin

Alpha-naphthylisothiocyanate (ANIT) is a toxicant that is widely used in rodents to model human intrahepatic cholestasis. The aim of the study is to investigate whether effects of dioscin on ANIT-induced cholestasis are related to changes in expression of hepatic transporters in rats. Effects of dioscin on cholestasis were examined by histology and biochemical marker levels. The functional changes of hepatic transporters were determined by in vitro, in situ and in vivo. qRT-PCR and western blot were used to assess the expression of hepatic transporters in cholestatic rats. Dioscin administration could ameliorate cholestasis, as evidenced by reduced biochemical markers as well as improved liver pathology. The uptakes of organic anion transporting polypeptide (Oatp) substrates were altered in liver uptake index in vivo, perfused rat liver in situ and isolated rat hepatocytes in vitro in cholestasis rats. qRT-PCR and western blot analysis indicated co-treatment of ANIT with dioscin prevented the adaptive down-regulation of Oatp1a1, 1b2, and prompted the up-regulation of Oatp1a4, multidrug resistance-associated protein (Mrp) 2 and bile salt export pump (Bsep). In addition, concerted effects on Mrp2 and Bsep occurred through up-regulation of small heterodimer partner by activating farnesoid X receptor. Dioscin might prevent impairment of hepatic function by restoring hepatic transporter expression.

Topics: 1-Naphthylisothiocyanate; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 11; ATP-Binding Cassette Transporters; Cholestasis, Intrahepatic; Diosgenin; Estrone; Hepatocytes; Liver; Male; Multidrug Resistance-Associated Protein 2; Organic Anion Transporters; Protective Agents; Rats, Wistar; Receptors, Cytoplasmic and Nuclear; RNA, Messenger

The objective of this study was to clarify the mechanism underlying hepatic uptake of dioscin (diosgenyl 2,4-di-O-a-L-rhamnopyranosyl-p-D-glucopyranoside), an herbal ingredient with antihepatitis activity, in rats and humans. The liver uptake index (LUI) in vivo, perfused rat liver in situ, rat liver slices, isolated rat hepatocytes, and human organic anion-transporting polypeptide (OATP)-transfected cells in vitro were used to evaluate hepatic uptake of dioscin. Values of 11.9% ± 1.6% and 15.0% ± 0.9% of dose for uptake of dioscin were observed by LUI in vivo and perfused rat livers in situ, respectively. The time course of dioscin uptake by rat liver slices was temperature-dependent. Uptake of dioscin by rat liver slices and isolated rat hepatocytes was inhibited significantly by Oatp modulators, such as ibuprofen (Oatp1a1 inhibitor), digoxin (Oatp1a4 substrate), and glycyrrhizic acid (Oatp1b2 inhibitor), but not by TEA or p-aminohippurate. Uptake of dioscin in rat hepatocytes and OATP1B3-human embryonic kidney (HEK) 293 cells indicated a saturable process with a Km of 3.75 ± 0.51 μM and 2.08 ± 0.27 μM, respectively. (-)-Epigallocatechin gallate, cyclosporin A, rifampicin, and telmisartan inhibited transport of dioscin in OATP1B3-HEK293 cells. However, transcellular transport of dioscin in OATP1B1- or OATP1B1/multidrug resistance-associated protein 2-Madin-Darby canine kidney strain II cells was not observed. These results indicate that hepatic uptake of dioscin is involved in OATP1B3 in humans, and multiple Oatps might participate in this process in rats.

Topics: Animals; Diosgenin; HEK293 Cells; Humans; In Vitro Techniques; Liver; Male; Organic Anion Transporters; Rats; Rats, Wistar