Skip Navigation
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

National Institute of Environmental Health Sciences

Use this QR code to view the newest version of this document
Use this QR code to view the newest version of this document

Your Environment. Your Health.

Publication Detail

Title: Mechanisms of hepatic methylmercury uptake.

Authors: Ballatori, N; Truong, A T

Published In J Toxicol Environ Health, (1995 Nov)

Abstract: The mechanism by which methylmercury is cleared from hepatic portal blood was examined in isolated rat livers perfused single-pass with Krebs-Henseleit buffer. [203Hg]Methylmercury (0.24-24 microM) was infused over a 30-min interval, followed by a 30-min washout, as a complex with the endogenous ligands L-cysteine (CH3Hg-L-cys), glutathione (CH3Hg-SG), and serum albumin (CH3Hg-albumin), or as a complex with dithiothreitol (CH3Hg-DTT), chloride (CH3HgCl), and the D-enantiomer of cysteine (CH3Hg-D-cys). The sulfhydryl-containing compounds were added at a 10-fold molar excess. When administered as the albumin complex, only a small fraction of the [203Hg]methylmercury was cleared from perfusate (approximately 8%) and excreted into bile (0.7%). Hepatic uptake and biliary excretion of methylmercury was considerably higher for the other complexes: The percent of the dose recovered in liver tissue and bile was, respectively, CH3Hg-albumin, 6.9 and 0.7; CH3Hg-L-cys, 15.7 and 2.3; CH3Hg-D-cys, 27.1 and 2.8; CH3Hg-SG, 17.7 and 2.1; CH3HgCl, 66.5 and 3.2; and CH3Hg-DTT, 70.1 and 19.8. For the dithiothreitol complex, hepatic extraction of methylmercury was nearly complete during single-pass perfusion. A comparison of hepatic removal of increasing doses of CH3Hg-L-cys and CH3Hg-D-cys revealed little difference in uptake between these two enantiomers. Moreover, the fraction of methylmercury removed was similar when infused at concentrations of 0.24, 2.4, and 24 microM, indicating no saturability of uptake within this dose range. Methylmercury was not hepatotoxic at concentrations up to 24 microM if administered as a mercaptide; however, the chloride complex (CH3HgCl) produced cholestasis and an increase in perfusion pressure at a concentration of only 0.24 microM. These findings indicate that hepatic methylmercury uptake and toxicity are dependent on the chemical form in blood plasma. Uptake was faster when methylmercury was present as a cysteine or glutathione complex, as compared to the albumin complex; however, the lack of stereoselectivity indicates that the uptake process may be relatively unselective.

PubMed ID: 7473862 Exiting the NIEHS site

MeSH Terms: No MeSH terms associated with this publication

Back
to Top