The effect of pretreatment of rats with the peroxisome proliferator 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) on sulphobromophthalein excretion from the isolated perfused rat liver has been investigated and compared with the effect of clofibrate which is also a peroxisome proliferator. 2. Rats fed 2,4,5-T at a dose of 0.25% in the diet showed a decrease in food intake, compared with controls and clofibrate-fed rats. 3. Treatment with either 2,4,5-T or clofibrate was associated with significant inhibition of the biliary excretion of unchanged, conjugated, and total sulphobromophthalein from perfused rat liver, compared with diet-matched controls. 4. There was a decrease in bile flow in the clofibrate-treated group, but not in the 2,4,5-T-treated group. 5. The results of the present study confirm previous studies that have shown an association between peroxisome proliferation treatment and inhibition of glutathione S-transferase-mediated sulphobromophthalein excretion.
