Disposition of some sulphur-containing hexachlorobenzene (HCB) metabolites: affinity of methylsulphonylpentachlorobenzene for the gray matter of brain, the lungs and the adrenal zona reticularis.

The distribution of methylsulphonylpentachloro-[14C]benzene (I), methylthiopentachloro-[14C]benzene (II), 1,4-bis(methylthio)tetrachloro-[14C]benzene (III) and 1,2,4-tris(methylthio)trichloro[14C]benzene (IV) was studied after intravenous injection in mice. The administration of I resulted in a rapid and selective accumulation of radioactivity in the gray matter of the brain, the lung and the zona reticularis of the adrenal cortex. In mice pretreated with metyrapone, or with high dose of unlabelled I, the radioactivity in the tissues was increased, whereas pretreatment with diethyl maleate did not change the disposition of I. In mice injected with II-IV no site of selective accumulation in the tissues was observed. Similarly to I, compounds II-IV were rapidly excreted in bile/faeces and urine. It is proposed that the sulphone group is essential for the high affinity of I for the brain, lung and adrenal cortex.