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DIFFERENCES BETWEEN RATS AND MICE IN THE IMMUNOSUPPRESSIVE ACTIVITY OF 2-METHOXYETHANOL AND 2-METHOXYACETIC ACID
Citation:
Smialoqicz, R., M. Riddle, W. Williams, D. Andrews, R. Luebke, AND C. Copeland. DIFFERENCES BETWEEN RATS AND MICE IN THE IMMUNOSUPPRESSIVE ACTIVITY OF 2-METHOXYETHANOL AND 2-METHOXYACETIC ACID. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/335 (NTIS PB92232974), 1992.
Description:
In the present study, the immunosuppressive potential of ME and MAA was evaluated in young adult female Fischer 344 rats and C57BL/6J mice. ats and mice ware dosed by gavage with either ME or in water, at dosages ranging from 90 to 400 mg/kg/d, for 1 consecutive days. ats and mice were examined for alterations in body, spleen and thymus weights, and mitogen-induced proliferation of splenic lymphocytes in vitro; separate groups were employed for the antibody plaque-farming cell (PFC) response to trinitrophenyl- lipopolysaccharide (TNP-LPS). ats dosed At 100-400 mg/kg/d ME and rats dosed at 50-400 mg/kg/d had decreased thymus weights in the absence of decreased body or spleen weights. ymphoproliferative (LP) responses to concanavalin A (Con A), hytohemagglutinin (PHA), pokeweed mitogen (PWM) and Salmonella typhimurium mitogen (STM) were all reduced in rats treated with all dosages of ME and at dosages of MAA at or greater than 100mg/kg/d. In contrast to the effects of ME and MAA on these end points in the rat, no thymic involution or suppression of LP responses were observed in mice dosed at 50-400 mg/kg/d. The PFC response to TNP-LPS was suppressed in rats dosed with either ME or MAA at dosages of 100-400 mg/kg/d. E and MAA however, failed to suppress the PFC response in mice immunized with TNP-LPS. These results indicate that unlike rats, mice are insensitive to the immunosuppressive effects of ME and MAA at the dosages employed in this study. hether the different sensitivities of these two rodent species to ME- and MAA-induced immunosuppression is due to immunologic, pharmacokinetic or metabolic differences within each species remains to be determined.