Dichloro-2,2-bis(p-chlorophenyl)ethane, and 1-Chloro-2,2-bis(p- chlorophenyl)ethene in the Hamster1

The urinary metabolites of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (ODD), and 1-chloro-2,2-bis(p-chlorophenyl)ethene in female hamsters are reported. The principal metabolite of both DDT and ODD is 2,2-bis(p-chlorophenyl) acetic acid. DDTand DDDtreated animals also excreted small amounts of DDD, 1-chloro2,2-bis(p-chlorophenyl)ethene, 1,1 -dichloro-2,2-bis-(p-chlorophenyl)ethene, 2-hydroxy-2,2-bis(p-chlorophenyl)acetic acid, and 2,2-bis(p-chlorophenyl)ethanol. 1-Chloro-2,2-bis(p-chlorophenyl)ethene is metabolized to afford significant amounts of 2,2-bis(p-chlorophenyl)acetic acid, 2,2-bis(p-chlorophenyl)ethanol, 2-hydroxy-2,2-bis(p-chlorophenyl)acetic acid, 2,2-bis(p-chlorophenyl)acetaldehyde, and 1,1-bis(p-chlorophenyl) ethan-1,2-diol. These results indicate that the metabolic dispo sition of DDT in the hamster, a species refractory to DDT tumorigenicity, is very similar to that observed previously in the mouse, a species sensitive to DDT tumorigenicity. The one exception is that the hamster is not nearly as efficient as the mouse in converting DDT to 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene. a metabolite that is tumorigenic in both species. INTRODUCTION We have previously investigated the metabolism of DDT,3 DDD, and DDMU in the mouse and demonstrated that metabo lism of DDT affords small quantities of DDMU epoxide, as evidenced by excretion of «OH-DDA in mouse urine (10, 11). This epoxide was shown to be mutagenic in the Ames system without enzymie activation (10). It was also suggested that DDA, the major urinary metabolite of DDT, does not arise from a sequential metabolic pathway, as proposed previously (3,6,1517) (Chart 1) but rather is produced by hydroxylation of the chlorinated side chain of DDD (Chart 2) (11). A hydroxylation of this type would initially afford DDA-CI. This acid chloride can hydrolyze to DDA or react with other nucleophilic cellular mole cules. DDA-CI, along with DDMU epoxide, could, via the forma tion of covalent adducts of DNA, account for the tumorigenicity in the mouse (14,22,23). The hamster, in contrast to the mouse, 1This work was supported by Grant R01 CA24554 from the National Cancer Institute. 2To whom requests for reprints should be addressed. 3The abbreviations used are: DDT, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane; DDD, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane; DDMU, 1-chlorc-2.2bis(p-chlorophenyl)ethene; DDMU epoxide, 1,2-epoxy-1-chtoro-2,2-bis(p-chlorophenyl)ethane; aOH-DDA, 2-hydroxy-2,2-bis(p-chloropnenyl)acetic acid; DDA, 2,2bis(p-chlorophenyl)acetic acid; DOA-CI, 2.2-bisip-chlorophenyl)acetyl chloride; HPLC, high-performance liquid chromatography; DDOH, 2,2-bis(p-chlorophenyl)ethanol; DDE. 1,1-dichloro-2.2-bis(p-chlorophenyl)etriene; DDCHO, 2,2bis(p-chlorophenyl)acetaldehyde: DDNU-diol 2.2-bis(p-chlorophenyl)etharv1.2dtol. Received October 25, 1982; accepted February 28, 1983. is refractory to DDT tumorigenesis (1, 5, 12); therefore, the metabolism of DDT in the hamster was studied to determine if a difference in metabolism, such as the production of DDMU epoxide or DDA-CI, could account for the species difference exhibited by DDT. MATERIALS AND METHODS Chemicals. Radioactive [p/»eny/-U-14C]DDD(specific activity, 1.80 mCi/mmol) and [p/ieny/-3H]DDT (specific activity, 4.65 mCi/mmol) were purchased from California Bionuclear Corp. (Sun Valley, Calif.) and New England Nuclear (Boston, Mass.), respectively. The DDMU was prepared as reported previously (13). The [3H]DDT was purified by preparative HPLC [column, 22.1-mm x 25-cm Zorbax ODS (Dupont Instruments, Wilmington, Del.); solvent, 10% H2O-90% CH3OH; flow rate, 10 ml/min; detection, 238 nm] and shown to be pure by analytical HPLC [column, 4.6-mm x 25-cm Ultrasphere ODS Su (Altex, Berkeley, Calif.); solvent, 9% H2O-91% methanol; flow rate, 1.0 ml/min; detection, 238 nm]. The I':C|DDD was diluted with DDD to give a final specific activity of 0.134 mCi/mmol, and the [3H]DDT was diluted with DDT to give a specific activity of 2.4 mCi/mmol. DDA, DDOH, DDE, and A/-methyl-A/'-nitro-A/nitrosoguanidine were purchased from Aldrich Chemical Co., Inc. (Mil waukee, Wis.). Other compounds, 1-1-txs(p-chlorophenyl)ethene, 1chloro-2,2-bis(p-chlorophenyl)ethane, DDCHO, methyl 2-hydroxy-2,2bis(p-chlorophenyl)acetate, methyl 2,2-bis(p-chlorophenyl)acetate, and DDNU-dtol, were prepared by methods reported previously (11). Animal Treatment Female Syrian golden hamsters were used for metabolism studies. The animals weighed approximately 130 g and were from the Eppley Institute colony. The DDT (100 mg/kg containing 124.7 i<Ci of [3H]DDT), DDD (500 mg/kg containing 23.5 nd of [14C]DDD), and DDMU (500 mg/kg) were dissolved in 0.4 ml of olive oil and administered by gavage. For each compound, 3 pairs of hamsters were kept in glass metabolism cages (Crown Scientific, Oriand Park, III.) that allowed sep arate collection of urine and feces. Collections were made at 24-hr intervals, with a total collection time of 72 hr. The collectors on the metabolism cages were submerged in solid CO2 to freeze samples as they were excreted. During the study, the hamsters were removed from the cages for 2 hr every 24 hr and given access to food. Water was provided ad libitum. Metabolite Analysis. Samples from DDTand DDD-treated hamsters were examined by reverseand normal-phase HPLC, as described previously (10). Samples from DDMU-treated hamsters were analyzed by gas-liquid chromatography (11).