Estradiol 17-(β-D-Glucuronide) (sodium salt hydrate)

Estradiol 17-(β-D-glucuronide) (E₂17G) is an estrogen metabolite formed in the liver and subsequently excreted in bile.¹ It acts as a substrate of the multidrug resistance protein 2 (MRP2; K_m = 75 µM), and through MRP2-mediated transport, functions as a cholestatic agent, decreasing bile flow.^1,2 In addition to binding to the MRP2 transport site, E₂17G has been shown to bind to an allosteric site that through positive cooperativity activates its own transport via MRP2 and the transport of other MRP2 substrates, including the non-cholestatic estrogen metabolite, estradiol 3-(β-D-glucuronide) .^2,3 E₂17G has also been reported to be transported by MDR1, MRP1, MRP3, MRP4, MRP7, ABCG2 (a breast cancer resistance protein transporter), and the rat organic anion-transporting polypeptides 1-4.²

1.Loe, D.W., Almquist, K.C., Cole, S.P., et al.ATP-dependent 17β-estradiol 17-(β-D-glucuronide) transport by multidrug resistance protein (MRP). Inhibition by cholestatic steroidsThe Journal of Biological Chemisty271(16)9683-9689(1996) 2.Gerk, P.M., Li, W., and Vore, M.Estradiol 3-glucuronide is transported by the multidrug resistance-associated protein 2 but does not activate the allosteric site bound by estradiol 17-glucuronideDrug Metabolism and Disposition32(10)1139-1145(2004) 3.Gerk, P.M., Li, W., Megaraj, W., et al.Human multidrug resistance protein 2 transports the therapeutic bile salt tauroursodeoxycholateJournal of Pharmacology and Experimental Therapeutics320(2)893-899(2007)