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Final Progress Reports: Michigan State University: Toxic Chemical Influences on In Vivo and In Vitro Reproduction

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Superfund Research Program

Toxic Chemical Influences on In Vivo and In Vitro Reproduction

Project Leader: Lynwood G. Clemens
Grant Number: P42ES004911
Funding Period: 1995 - 2000

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Final Progress Reports

Year:   1999 

Completion of PCB project: Since submission of the grant application the researchers have completed their analysis of the effects of PCBs on reproductive behavior in laboratory rats. In general perinatal exposure to Aroclor 1254 or 1221 affected female sexual behavior but had little effect on male behavior. These mixtures also had specific and complex effects on brain dopamine systems.

TCB Studies: Because analysis of PCB mixtures made it difficult to ascertain the mechanism by which PCBs were having their effects, researchers initiated studies using the TCB congeners 3,4,3',4' and 2,4,2',4', -tetrachlorobiphenyl. Analysis of the effects of prenatal exposure to these congeners revealed that 3,4,3',4', TCB significantly decreased female sexual responding, whereas 2,4,2',4' TCB showed no effect. Male offspring were not affected by either congener. Carrying this analysis to the F1 generation, the investigators also tested the behavior of the offspring of animals exposed to these congeners. The data are still being analyzed for the female F1s. Most of the male offspring were lost because of exposure to an SDA virus introduced into the colony by the breeder.

Because exposure to TCBs appeared to affect the mother's behavior and because this could influence the subsequent behavior of her offspring, project researchers completed a pilot study to determine an efficient schedule for observing mother-pup interactions using a video analysis. Following completion of that pilot project, an intensive study of TCB treatment on development of reproductive behavior and brain dopamine systems was initiated. Since earlier work was criticized for using too limited a range of the dosages, the dose range has been extended. This work is now in progress.

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