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DEVELOPMENTAL EXPOSURE TO DI-N-BUTYLTIN DICHLORIDE (DBTC): IMMUNOTOXIC AND NEUROTOXIC EVALUATION
Citation:
Luebke, R W., S Barone, C B. Copeland, L. D. White, AND S. Jenkins. DEVELOPMENTAL EXPOSURE TO DI-N-BUTYLTIN DICHLORIDE (DBTC): IMMUNOTOXIC AND NEUROTOXIC EVALUATION. Presented at Society of Toxicology 42nd Annual Meeting, Salt Lake City, Utah, March 9-13, 2003.
Description:
Organotins are incorporated as stabilizers in PVC water supply pipe. Particularly when new, mono- and di-substituted methyl- and butyltins leach from the pipe and are thus of regulatory concern to EPA. These contaminants have adverse effects on both the immune and nervous systems under laboratory conditions. The toxicity of other members of this class, tributyltin and dioctyltin, is greater in the immature immune system; thus, DBTC was evaluated following combined gestational and lactational exposure in offspring of Wistar rats exposed by gavage with 0 (olive oil), 2.5 or 5.0 mg DBTC/kg/d from gestational day 6 until weaning on post-natal day (PND)21. Separate groups of pups born to normal dams were exposed to the 10 doses of the same concentrations by gavage, 3 time/wk from PND3 through PND22. Immune system endpoints included body, spleen and thymus weights, antibody responses to a T-dependent antigen and delayed hypersensitivity responses. Potential neurotoxicity was evaluated by measuring brain weight. Immune function was not affected by either exposure regimen, although lower body weights and increased spleen and thymus weights were noted on PND38 in nonimmunized rats at the highest dose, suggesting that an earlier decrease in lymphoid organ weight may have occurred. Normal immune function, particularly in the directly-dosed pups, was an unexpected finding, given the demonstrated immunotoxicity of organotins in adult rats. Direct exposure to DBTC caused a dose-related delay in brain weight gain on PND38 at both exposure levels. Brain weights were similar in control and low dose pups on PND48; however, there was essentially no increase in brain weight in higher dose-group pups between PND30-PND48, in spite of a 25% increase in body weight. Based on these data, it appears that the developing nervous system may be more sensitive to DBTC than is the immune system. (This abstract does not reflect EPA policy.)
above from the SOT website