US EPA

1482721 

Journal Article 

Biliary Metabolites of 2,6-Diisopropylnaphthalene in Rats 

Kojima, S; Honda, T; Kiyozumi, M 

1985 

Yes 

Bulletin of Environmental Contamination and Toxicology
ISSN: 0007-4861
EISSN: 1432-0800 

NIOSH/00169660 

35 

6 

745-749 

The biliary metabolism of 2,6-diisopropylnaphthalene (24157811) (DIPN) was studied in rats. Male Wistar-rats with cannulated bile ducts were administered 100mg/km DIPN orally. The bile was collected for 24 hours after dosing and analyzed for metabolites by gas liquid chromatography. Metabolites of DIPN excreted in the bile amounted to about 17 percent of the dose. Both conjugated and unconjugated metabolites were excreted. Total excretion of conjugated metabolites was much smaller than that of unconjugated metabolites. 2,6-Naphthalenedi(2-propan)-2-ol (26NDP) and 2,6-naphthalenedi-2-propionic-acid (26NDPA) were the major unconjugated biliary metabolites. Smaller amounts of 2-(6-(1-hydroxy-1-methyl)ethylnaphthalene-2-yl)-2-propionic-acid, 2-(6-(1-hydroxy-1-methyl)ethylnaphthalene-2-yl)-2-hydroxypropionic-acid (OHMENPA), and 2-(6-(1-hydroxy-1-methyl)ethylnaphthalene-2-yl)-1,2-propanediol were found. Unchanged DIPN was also identified. The retention times of the conjugated metabolites corresponded to those of the unconjugated metabolites. The authors note that three of the metabolites (26NDP, 26NDPA, and OHMENPA) have been isolated in rat urine in previous studies. 26NDPA is apparently reabsorbed from the gastrointestinal tract and metabolized to OHMENPA, which is primarily excreted in the urine. The excretion pattern of biliary metabolites of DIPN, however, is different from that of urinary metabolites. 

DCN-157504; Aromatic hydrocarbons; Biotransformation; Naphthalenes; In vivo studies; Laboratory animals; Biliary system; Oxidative metabolism; Chromatographic analysis