Correlation of systemic and biochemical effects of PBB with behavioral effects.

Rats were given PBB orally at 1, 3, and 6 mg/kg (or vehicle as control) daily for 20 days. Some animals were sacrificed immediately while the food intake of remaining animals was limited to attain and maintain 80% of normal body weight. No effect of PBB upon body weight was observed for any of the dose levels employed. Immediately after dosing, liver/body weight ratios were 110% of controls for the 1 mg/kg group and 152% for the 3 and 6 mg/kg groups; after weight reduction for 2-6 months liver/body weight ratios for all 3 dose groups were 160-170% of controls. In the absence of body fat, most tissues exhibited dose-dependent retention of PBB 2-6 months after dosing with highest levels in liver followed by kidney. In 6 mg/kg rats weight-reduced for 6 months, liver AHH activity was 613% of controls; in rats sacrificed immediately after dosing, liver AHH activity was dose-related but appeared to reach maximal value at the 3 mg/kg dose. Both calcium binding to synaptic plasma membranes and calcium uptake by intact synaptosomes was significantly reduced in the brains of 1 mg/kg PBB rats, but not affected in preparations from 3 and 6 mg/kg animals.