Electron microscopic study of livers from mice fed 167 ppm polybrominated biphenyl (PBB) for 12 weeks showed hepatocytes with nuclei containing varied amounts of lipid inclusions. The inclusions appeared as spherical vacuoles free in the nuclear matrix. This is the first report of the induction of lipid inclusions within the nucleus by a halogenated hydrocarbon.

Electron microscopic study of livers from mice fed 167 ppm polybrominated biphenyl (PBB) revealed mitochondrial abnormalities which consisted of both alterations in size and the formation of crystalline-like inclusions within the mitochondrial matrix. These inclusions appeared as parallel arrays of rods and were found in elongated mitochondria which contained few cristae. The findings are briefly described and the possible significance of such inclusions in relation to mitochondrial aberrations are discussed.