Autoradiographic study of the localization of 2,2', 4,4', 5,5'-hexachlorobiphenyl in liver and skin tissue after in vitro uptake

Abstract

Cellular distribution of the lipophilic environmental pollutant, 2,2', 4,4', 5,5'-hexachlorobiphenyl (6-CB), was determined by autoradiography after in vitro uptake of the 14C-labeled compound into liver and skin tissue preparation. Light microscopic data of cryostat sections showed that 6-CB is homogeneously distributed in liver tissue. In skin the distribution pattern depended on the conditions of incubation. If skin slices were incubated with 6-CB prior to preparation of cryostat thin sections, the epidermis was practically free of 6-CB and the radioactivity was found mainly in the stratum reticulare of the dermis. If, however, cryostat sections of skin were directly incubated, 6-CB was more homogeneously distributed with an accumulation in the epidermis. Liver and skin sections delipidated with acetone or 95% ethanol prior to incubation with 6-CB took up very little of the compound. Delipidation of sections preincubated with 6-CB resulted in total extraction of 6-CB. The results suggest that human stratum corneum is a barrier to the penetration of 6-CB and that this compound is located in lipid structures of liver and skin.