Study Findings Withdrawn

August 1, 1997

Judith Zwolak

Tulane researchers have formally withdrawn a widely publicized study suggesting that chemicals, which act like weak mimics of the hormone estrogen when alone, produce a much stronger effect when acting together.

The report of the study, "Synergistic activation of estrogen receptor with combinations of environmental chemicals," appeared in the June 7, 1996, issue of Science magazine.

In a letter published in the July 25, 1997, issue of Science, John McLachlan, the corresponding author of the paper and director of the Tulane/Xavier Center for Bioenvironmental Research (CBR), writes, "We have conducted experiments duplicating the conditions of our earlier work, but have not been able to replicate our initial results."

He continues, "...despite the enthusiasm it generated, it is clear that any conclusions drawn from this paper must be suspended until such time, if ever, the data can be substantiated."

In the letter, McLachlan says that he and the study's other authors have been conducting experiments for the past six months to clarify the mechanisms behind their earlier study, but have not been able to explain their earlier findings to their satisfaction.

"Taken together, it seems evident that there must have been a fundamental flaw in the design of our original experiment," he writes. The CBR laboratory will continue to work aggressively in the field of environmental endocrinology, McLachlan writes in the letter.

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