Enterohepatic circulation of bis(p-chlorophenyl)acetic acid in the rat.

After intravenous administration of 14C-bis(p-chlorophenyl)acetic acid (DDA) to biliary cannulated rats, 97% of the dose of 14C was recovered in the bile in 24 hr. When 14C-1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT) was administered orally, approximately 8% of the dose was recovered in the bile in 3 days. The metabolite in bile in each case was a conjugate of DDA, probably with glucuronic acid. Thus less than 10% of a single dose of DDT was metabolized to DDA. The biliary metabolite was shown by two methods to undergo extensive enterohepatic circulation. The role of biliary excretion and enterohepatic circulation in the elimination of DDT metabolites is discussed.