estradiol-3-glucuronide and Cholestasis

Estradiol-17beta-D-glucuronide (E2-17G) induces an acute but reversible inhibition of bile flow after its intravenous administration to rats, due in part to the endocytic retrieval of the canalicular multidrug resistance-associated transporter protein 2 and the bile salt export pump, transporters that contribute to bile flow. Decreased bile salt-independent bile flow (BSIF) is also involved and persists during the phase of recovery from cholestasis. Because glutathione and HCO3- are major contributors to BSIF, we evaluated changes in their biliary excretion and the hepatic content of total glutathione during E2-17G-induced cholestasis. E2-17G acutely decreased bile flow and biliary excretion of total glutathione by about 80%; glutathione excretion was still inhibited at 80 min and 120 min, even though bile flow was partially and totally restored, respectively. Neither liver glutathione content nor the proportions of oxidized glutathione in bile and liver were affected by E2-17G at any time. HCO3- concentrations in bile were unchanged, so that secretion paralleled variations in bile flow. In the isolated perfused liver, addition of E2-17G decreased both bile flow and the biliary concentration of glutathione, whereas addition of its noncholestatic isomer estradiol-3-D-glucuronide (E2-3G) did not inhibit bile flow, but significantly reduced the concentration of glutathione in bile. The bile:liver concentration ratios of glutathione were significantly decreased in vivo by E2-17G and in the perfused liver by E2-17G and E2-3G. These data indicate that E2-17G cis-inhibits the canalicular transport of glutathione and thus contributes to the cholestatic effect by inhibiting BSIF.

Topics: Animals; Anions; Biliary Tract; Cholestasis; Estradiol; Female; Glutathione; Glutathione Disulfide; Rats; Rats, Sprague-Dawley

Chlorpromazine at a concentration of 250 microM and estradiol-17 beta-D-glucuronide at 17.5 microM on infusion led to a sharp reduction in bile flow by the in vitro perfused rat liver. This was accompanied by fragmentation and a loss of canalicular microvilli, dilatation of canaliculi, and thickening of pericanalicular ectoplasm. Less prominent were the smooth endoplasmic reticulum dilatation, lysosomal lamination, and the appearance of amorphous bile in hepatocyte cytoplasm. The bile flow and electron microscopy appearance were restored to normal by infusion of tauroursodeoxycholate in a concentration of 5 mumols/min for the estradiol-17 beta-D-glucuronide-induced cholestasis and 1.5 mumol/min for the chlorpromazine-induced cholestasis. Changes in ultrastructure paralleled changes in bile flow. These observations demonstrate the feasibility of electron microscopy studies on the perfused liver, and the rapidity with which cholestatic changes appear.

Topics: Animals; Bile; Chlorpromazine; Cholestasis; Estradiol; In Vitro Techniques; Kinetics; Liver; Microscopy, Electron; Perfusion; Rats; Taurochenodeoxycholic Acid; Time Factors

Estradiol-17 beta-(beta-D-glucuronide) (E217G) was shown to be cholestatic in the isolated perfused female rat liver. Doses of 0.85, 1.3, 1.7 and 2.1 mumol decreased bile flow maximally at 15 to 30 min by 29, 37, 68 and 76% respectively. Approximately 95% of a dose of [3H]E217G was cleared from the perfusate in 30 min and was secreted in bile, with 93, 85, 71 and 55% of the dose appearing in bile within 120 min after doses of 0.85, 1.3, 1.7 and 2.1 mumol, respectively. Neither vehicle nor 1.7 mumol of estradiol-3-(beta-D-glucuronide) (E23G) significantly altered bile flow. Infusion of taurocholate at 40 and 60 mumol/hr, respectively, partially and completely protected against the cholestasis induced by 1.7 mumol of E217G. The log dose-response curve for E217G-induced cholestasis was much steeper and was shifted to the right in the presence of a 60 mumol/hr infusion of taurocholate. Infusion of taurocholate at 80 mumol/hr in the absence of E217G or E23G decreased bile flow by 79%. However, addition of 1.7 mumol of either E217G or E23G offered marked protection against taurocholate-induced cholestasis and increased bile acid secretion. Higher doses (3.4 mumol) of E217G or E23G further increased bile flow and bile acid secretion. A model system is presented to explain the mutual protection against cholestasis.

Topics: Animals; Bile; Bile Acids and Salts; Biological Transport; Cholestasis; Dose-Response Relationship, Drug; Estradiol; Female; Perfusion; Rats; Rats, Inbred Strains; Sulfobromophthalein; Taurocholic Acid