Effects of pure chlorobiphenyls (2,4',5-trichlorobiphenyl or 2,2',4,4',5,5'-hexachlorobiphenyl) on the disappearance of 14C from the blood plasma after intravenous injection of 4-14C-progesterone and on the hepatic drug metabolizing system in the female rat.

Effects of two pure chlorobiphenyls (2,4',5-trichlorobiphenyl or 2,2',4,4',5,5'-hexachlorobiphenyl) on the hepatic drug metabolizing system and on the elimination rate of 14C from the blood after intravenous injection of 4(-14)C- progesterone have been studied in the female rat. The results obtained show that females pre-treated with small amounts of 2,2',4,4'5,5'-hexachlorobiphenyl (o.5 mg/day for 14 consecutive days) have significantly higher elimination rates of 14C (originating from intravenous injection of 4(-14C-progesterone) from the blood plasma, significantly higher content of hepatic cytochrome P-450 and significantly heavier livers than control females. On the other hand, trichlorobiphenyl (0.5 mg/day for 14 consecutive days) do not differ significantly from the results obtained from control females.