POLYCHLORINATED BIPHENYL (PCB) EFFECTS ON HEPATIC MIXED-FUNCTION OXIDASES AND PORPHYRIA IN BIRDS .2. AMERICAN KESTREL

1. In order to study the effects of polychlorinated biphenyls (PCBs) on American kestrels (Falco sparverius), groups of 6 female birds were fed toxic equivalent doses, estimated from rat studies, of either 2,3,3'4,4'-PCB (3 mg/kg/day) or 3,3',4,4',5-PCB (0.05 mg/kg/day) and a comparable dose of 2,2',4,4',5,5'-HxCB (4 mg/kg/day) for 4 weeks. 2. Livers were assayed for ethoxyresorufin OMICRON-deethylase (EROD), aminopyrine N-demethylase (APND) and aldrin epoxidase (AE) activity and also analyzed for concentrations of porphyrins by HPLC; abdominal fat was analyzed for residues of PCB congeners by GC/ECD. 3. Chronic dosing with 3,3',4,4',5-PCB (congener 126) caused significant induction of hepatic EROD and AE; dosing with 2,3,3'4,4'-PCB (congener 105) caused significant hepatic APND induction; dosing with 2,2',4,4',5,5'-HxCB (congener 153) caused significant induction of APND and AE. 4. None of the congeners had a significant effect on mean liver weight or mean hepatic porphyrin levels. 5. The data indicate that the relative response of kestrels to dosing with PCB congeners is different from both quail and rats.