Uptake, distribution, and metabolism of inhaled ethylmercuric chloride in the rat

Abstract

COMMUNICATED BY LOUIS LYKKENThe uptake and the tissue distribution of ethylmercuric chloride (EMC) by inhalation and oral administration were studied in adult female rats. The pulmonary uptake of EMC linearly increases with the time of exposure and is proportional to the concentration of EMC vapor. With the exception of stomach, intestine, and hair, the tissue distribution of 2 o 3 Hg from pulmonary uptake is quite similar to that from oral administration. The biological halflife of EMC in the organs is longer from pulmonary uptake than from oral administration. Kidney and liver convert EMC to inorganic mercury irrespective of the routes of administration. A small amourit of 2°3Hg is found in the fetus, and the fetal liver accumulates more 2°3Hg than the fetal kidney.Alkyl mercurial pesticides were introduced during the 1940s for seed dressing and, also, for control of fungus disease in plants. These mercury preparations usually contain methyl mercury and, to a less extent, ethyl mercury. The short-chained alkyl mercury salts vaporize easily at room temperature and poisoning occurs after exposure to these vapors CSwensson t952, Trachtenberg 1969). Studies on the uptake and distribution of mercury vapor through inhalation have been made in a number of animals (Gage 1961, Hayes and Rothstein 1962, Magos 1967, 1968, Berlin et al., 1969, Cassano et al. 1969. However, detailed reports are not available regarding the respiratory uptake of alkyl mercury compounds. The retention of dimethyl mercury after a single inhalation exposure by mice under slight anesthesia has been reported (Ost]und 1969) but the vapor concentrations used were not given. This paper reports the uptake, distribution, and metabolism of ethylmercuric chloride (EMC) in rats as the result of inhalation of EMC and, for comparison, ingestion of the chemical. Materials and methods2°3Hg-labeled ethylmercuric chloride (EMC3°3Hg) was prepared by an exchange reaction. One mmole of pure, recrystalized ethylmercuric chloride was dissolved in five 1Technical Paper No. 3496, Oregon Agricultural Experiment Station, Corvallis, Oregon.

Exposure to Mercury during the First Six Months via Human Milk and Vaccines: Modifying Risk Factors

“…They concluded that MeHg does not appear to be a good model for EtHg-containing compounds. In the rat model, Fang and Fallin 29 showed that nonenteral (inhaled) uptake of EtHg had a higher tissue distribution of 203 Hg (stomach, intestine, and hair) and a longer biological half-life of EtHg in organs 21 than oral administration. Acute exposure to inhaled EtHg, besides causing a much higher overall fetal death rate than orally administered EtHg, also caused a decrease in the number of offspring per litter.…”