Estradiol 17ß-d-glucuronide-induced impairment of MRP2 activity in rat hepatocytes involves NADPH oxidase-mediated oxidative stress.

SALAS, G; MEDEOT, AC; SCHUK, VS; ANDERMATTEN, RB; MISZCZUK, GC; CIRIACI, N; BAROSSO IR; SANCHEZ POZZI, EJ; ROMA, MG; BASIGLIO, CL; CROCENZI FA

Rosario

Congreso; Reunión Anual 2019 Sociedad Argentina de Fisiología; 2019

Sociedad Argentina de Fisiología

Estradiol 17ß-D-glucuronide (E17G) is an endogenousmetabolite of estradiol that is considered a mainresponsible of intrahepatic cholestasis of pregnancy.E17G induces acute cholestasis in animal models viaactivation of several kinase-mediated signaling pathwaysleading to an increased endocytosis and intracellularretention of canalicular transporters and the consequentcanalicular secretory failure. Oxidative stress has beenshown to induce internalization of canaliculartransporters and cholestasis. Here, we investigated thepossible involvement of oxidative stress in E17G-inducedimpairment of canalicular Mrp2 function. Transportfunction of Mrp2 was analyzed by the measurement ofcanalicular vacuolar accumulation (cVA) of glutathione-Smethylfluorescein(GS-MF), a fluorescent glutathioneconjugatedmetabolite of chloromethylfluoresceindiacetate (CMFDA) in rat hepatocyte couplets (RHC), andalso by measuring the initial transport rate (ITR) of GS-MFin sandwich-cultured rat hepatocytes (SRH). The role ofreactive oxygen species (ROS) in E17G-induced Mrp2function impairment was evaluated by preincubatinghepatocytes for 15 to 30 min with the antioxidantcompounds vitamin C (VitC), mannitol (Man), N,N´-diphenyl 1,4-phenylenediamine (DPPD), or with apocynin(Apo), a specific inhibitor of the ROS-producing enzymeNADPH oxidase (NOX), prior to a 20-min exposure toE17G. cVA of GS-MF, expressed as percent of control,was significantly reduced by E17G (45±2, p