Mechanisms of absorption of inorganic mercury from rat small intestine. III. Comparative absorption studies of inorganic mercuric compounds in vitro.

The transport of various inorganic mercuric compounds (HgX2s) was compared in everted intestinal sacs and intestinal brush border membrane vesicles (BBMV) of the rat. The preparations were incubated in a medium containing 10(-4) M HgX2 at pH 5.5, 6.4 or 7.4, respectively. The order of transport through the intestinal wall at each pH (HgOAc)2 greater than HgCl2 greater than Hg(SCN)2 greater than HgBr2 greater than Hg(CN)2) was the reverse order of their stability constants, and an increase in pH tended to increase the transport of HgX2. In the experiment with BBMV, similar results were obtained except for the transport of Hg(CN)2. These results suggest that the extent of transport of a certain HgX2 depends on its stability constant, and that the increase in pH promotes the transport possibly as a result of the conversion of HgX2 to Hg(OH)X and Hg(OH)2.