Related Experiment Video
Updated: Aug 19, 2026

Setting-up an In Vitro Model of Rat Blood-brain Barrier (BBB): A Focus on BBB Impermeability and Receptor-mediated Transport
Published on: June 28, 2014
Effects of ethinyl estradiol on substrate uptake and efflux by isolated rat hepatocytes
Abstract:
Ethinyl estradiol is a well documented, predictable cholestatic agent. The direct effects of this drug on hepatocellular uptake and efflux have been investigated. Uptake of taurocholate and ouabain, which are both actively transported, was inhibited, while uptake of cadmium, which occurs by a combination of facilitated and simple diffusion, was unaffected. The Vmax for taurocholate uptake was not altered by the presence of ethinyl estradiol, whereas the Km was increased, suggesting a reduced affinity of receptor for taurocholate. Efflux of taurocholate from pre-loaded cells remained unchanged in the presence of ethinyl estradiol. The data are not entirely consistent with an interference of Na+,K+-ATP ase by ethinyl estradiol being an important site of action. The observations may help to explain the mechanism of biliary dysfunction induced by ethinyl estradiol.
Related Concept Videos
Hepatic Drug Excretion: Enterohepatic Cycling
Post-release drugs and metabolites can be reabsorbed into the body from the intestine. For conjugated metabolites like glucuronides, reabsorption requires enzymatic hydrolysis by intestinal microflora. This...
Hepatic Drug Clearance: Role of Transporters
Physiological Pharmacokinetic Models: Incorporating Hepatic Transporter-Mediated Clearance
A recent model describes pravastatin's hepatobiliary excretion, mediated...
Effect of Hepatic Disease on Pharmacokinetics: Drug Dosing and Hepatic Blood Flow
Effect of Hepatic Disease on Pharmacokinetics: Active Drug, Metabolite and Fraction of Metabolized Drug
Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment

