This chapter summarizes work on the metabolism of tributyltin (TBT) by marine fauna and flora and how this metabolism may relate to some observed effects. Fish and crustaceans have an active cytochrome P-450 dependent monooxygenase system that oxidizes TBT to a series of hydroxylated derivatives. These hydroxylated derivatives are conjugated to sulfate or carbohydrate by phase-two enzyme systems, which facilitates the elimination of TBT. Molluscs have low cytochrome P-450 content and mixed function oxygenase activity, which result in TBT accumulation and slow depuration due to the low rate of TBT metabolism. Some of the TBT effects observed for molluscs include imposex in stenoglossan gastropods; shell thicken ing in oysters; reduced growth rates in mussels; and breakdown of sexual differentiation, oogenesis, and egg production in Ostrea edulis. I suggest that these effects are related to the slow metabolism of TBT, binding of TBT metabolites to cellular proteins, and inhibition of detoxifying enzyme systems (e.g. cytochrome P-450 systems and glutathione S-transferases) by TBT. TBT and hormones share common metabolic pathways, and many effects of TBT are hormonally regulated.
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- Metabolism of Tributyltin by Aquatic Organisms
Richard F. Lee
- Springer Netherlands
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