Pathology of polychlorinated biphenyls in rabbits.

Rabbits were administered, orally, 300 mg of polychlorinated biphenyl Aroclor 1221, 1242 or 1254 once a week for 14 weeks. Elevated SGPT and SGOT levels occurred in the male and female 1254- and male 1242-treated rabbits as early as 2 weeks. The female 1242-treated rabbits had increased SGPT and SGOT activities at 4 and 8 weeks, respectively. These serum enzyme activities in the 1221-treated rabbits were similar to the controls during the 14-week period. Serum cholesterol concentrations were moderately elevated in the 1254-treated males throughout the experiment. The BUN, serum proteins, liver ALA-synthetase and hematologic values were similar in all groups. The livers in the 1254- and 1242-treated rabbits were significantly enlarged compared to the 1221-treated and control animals. The earliest change was megalohepatocytosis which was followed by subcapsular midzonal necrosis. In the 1254-treated rabbits, the midzonal necrosis was diffuse and frequently included most of the central part of the lobule. Fibrous connective tissue replaced the necrotic part of the lobules in the more severely affected livers. The rough endoplasmic reticulum in the livers of the 1254-treated rabbits appeared to have been destroyed. There was also atrophy of the uteri in the 1254-treated rabbits.