Determination of 4,4'-methylene-bis(2-chloroaniline)-DNA adduct formation in rat liver and human uroepithelial cells by the 32p postlabeling assay.
DeBord-DG; Cheever-KL; Werren-DM; Reid-TM; Swearengin-TF; Savage-RE Jr.
Fundam Appl Toxicol 1996 Mar; 30(1):138-144
DNA adducts formation in rat liver in-vivo and human uroepithelial cells (HUC) in-vitro after exposure to 4,4'-methylene-bis(2- chloroaniline) (101144) (MOCA) was investigated using the phosphorus- 32 (P32) postlabeling assay. Male Sprague-Dawley-rats were administered MOCA at 7.5 to 5,000mg/kg by oral gavage or intraperitoneal injection. Rats were killed 24 hours later, and DNA was extracted from the liver. HUC were incubated with the MOCA metabolite N-hydroxy-MOCA at 2.5, 5.0 and 10 micromolar (microM) for 24 hours, and DNA was isolated. The nuclease-P1 enhancement procedure was used with the P32 postlabeling assay for the detection of DNA adducts. There were five DNA adducts detected in rat liver. The major adduct in rat liver DNA, Adduct-A, appeared in all treatment groups. The level of Adduct-A was higher after intraperitoneal administration than after oral administration of MOCA, and the level was approximately 12 fold higher in rats pretreated with phenobarbital. Only Adduct-A was detected in HUC at the three treatment levels, and the Adduct-A levels were similar at the three treatment levels. A second adduct was seen only at the 10microM treatment level. The authors conclude that the major DNA adduct detected both in rat liver and in HUC may be useful as a biomarker of exposure.
NIOSH-Author; DNA-adducts; In-vitro-studies; In-vivo-studies; Amines; Laboratory-animals; Cell-cultures; Carcinogens; Biological-monitoring; Anilines
Fundamental and Applied Toxicology