Effect of diethyl maleate on the biliary excretion rate of infused sulfobromophthalein-glutathione.

Diethyl maleate (DEM) was given intraperitoneally to rats in a dose (4.3 mmoles/kg) known to markedly decrease glutathione levels in liver. DEM induced a choleresis previously shown to be due to the osmotic activity of DEM conjugates (DEM-glutathione and subsequent metabolic products) excreted into bile. Coincident with the choleresis, the biliary excretory Tm for the infused glutathione conjugate of sulfobromophthalein (BSP-GSH) was depressed significantly. The data are interpreted as indicating that DEM-GSH conjugates compete with BSP-GSH conjugates for a canalicular carrier mechanism.