Dependence of biliary secretion of inorganic mercury on the biliary transport of glutathione

The interrelation between the biliary transport of glutathione (GSH) and of inorganic mercury was investigated in suckling and adult male and female rats. The 14-day-old rat secreted inorganic mercury into bile at one-seventh the rate of the 28-day-old rat. Development of the ability to secrete mercury paralleled development of the ability to secrete GSH. The inability of the 14-day-old rat to secrete mercury and GSH occurred despite hepatic tissue concentrations of both of these compounds which were similar to those of adult rats. In adult rats, inhibition of GSH secretion by sulfobromophthalein (BSP) administration resulted in a parallel inhibition of mercury secretion. Conversely, the increase in the rate of GSH secretion into bile after cysteine or GSH administration was accompanied by an increase in the rate of mercury secretion into bile. The changes in the biliary secretion of mercury and of GSH after treatment with cysteine or GSH were not closely parallel, probably because of the tissue redistribution of mercury effected by these sulfhydryl-containing compounds. Mercury secretion into bile was independent of the changes in bile flow produced by dehydrocholate (DHC) or hypertonic sucrose, but it was closely related to the rate of GSH secretion. Further, sex differences and individual variability in the biliary secretion of inorganic mercury were correlated with differing abilities to secrete GSH into bile. These results suggest that the biliary secretion of inorganic mercury is in large part dependent on the biliary transport of GSH.