BILIARY-EXCRETION OF ESTRONE METABOLITES IN THE RAT

We previously reported that sulfobromophthalein infusion inhibited the biliary excretion of estradiol glucuronides, whereas dibromosulfophth alein had no effect. In the present study, we examined the biliary exc retion of estrone metabolites in rats. Biliary excretion of a tracer d ose of intravenously injected [H-3]estrone to control rats or EHBR and effects of the infusion of sulfobromophthalein and dibromosulfophthal ein were studied. Biliary excretion of estrone metabolites was delayed in EHBR. Analysis of the biliary estrone metabolites revealed a marke d decrease of the glucuronides in EHBR. Sulfobromophthalein and dibrom osulfophthalein infusion (0.2 mu mol/min/100 g b.wt.) inhibited the bi liary excretion of estrone metabolites. However, the decrease in bilia ry excretion of the glucuronides was observed only with sulfobromophth alein that is excreted mainly as the glutathione conjugate. These find ings indicate that glucuronides of estrone and its metabolites are par tly excreted into bile by a canalicular organic anion carrier for sulf obromophthalein-glutathione, but not for dibromosulfophthalein.