Organ and cellular distribution of inhaled metallic mercury in the rat and Marmoset monkey (Callithrix jacchus): influence of ethyl alcohol pretreatment.

Abstract

Distribution of inhaled radioactive metallic mercury vapour (203Hg0) in rats and Marmoset monkeys (Callithrix jacchus), with or without pretreatment by ethyl alcohol or aminotriazole (rat), was studied by means of whole-body autoradiography, microautoradiography and scintillation counting of excised organs. Metallic mercury is oxidized by the catalase-H2O2 complex (Complex I) to the ionic form (Hg2+) and is known to be accumulated and retained in organs such as lungs, liver, myocardium, and brain, apparently after local oxidation in these organs. To this list of organs can be added the whole respiratory tract (nasal mucosa, trachea, and bronchi), a number of endocrine organs such as adrenal cortex, thyroid, corpora lutea of the ovaries, and interstitial tissues of the testes, the uvea and retina of the eye, and the salivary glands. In the liver, a regionalized pattern of distribution corresponding to the periportal hepatocytes was observed. Similarly, the subcapsular parts of the adrenal cortex (mainly the zona glomerulosa) were responsible for most of the adrenal mercury oxidation and retention. These organs (liver, adrenal) thus have a reserve capacity to oxidize Hg0. This is apparent also by the fact that ethyl alcohol and aminotriazole (known catalase inhibitors)--which depress oxidation and retention in most organs and whole body and thus increase blood concentrations of Hg0--cause an increased retention in most liver and adrenal cells.