Pass the disruption

Credit: Courtesy of Michael Skinner The paper: M.D. Anway et al., "Epigenetic transgenerational actions of endocrine disruptors and male fertility,"

By | September 1, 2007

<figcaption> Credit: Courtesy of Michael Skinner</figcaption>
Credit: Courtesy of Michael Skinner

The paper:
M.D. Anway et al., "Epigenetic transgenerational actions of endocrine disruptors and male fertility," Science, 308:1466-9, 2005. (Cited in 112 papers)

The finding:
A group led by Michael Skinner from Washington State University briefly exposed pregnant female rats to endocrine disruptors and found sperm defects in the F1 generation of male rats, which were passed through the male germ line to the F4 generation. Offspring of treated rats also had DNA methylation differences. "Potentially this transgenerational epigenetic mechanism could be how the environment is influencing disease," says Skinner.

The significance:
The study provided clear evidence of multigenerational effects of environmental exposure, says Andrea Gore, from University of Texas, Austin, who has since collaborated with Skinner's group.

The catch:
Doses used in the study were higher than those seen in the environment, the authors note. "All bets are off when you extrapolate the findings" to humans or other animals, says Randy Jirtle from Duke University. Skinner's group is now working to study the effects of dose on sperm viability.

The progress:
Skinner and colleagues allowed male offspring of treated rats to age six months to a year and found that a number of other conditions, such as kidney disease and breast tumors, were passed across generations (Endocrinol, 147: 5515-23, 2006). Jirtle says it will be important to identify the precise methylation effects that give rise to the phenotypes, "because epigenomes vary greatly [among] species."

Skinner's summary of the data:

Phenotype

Effect (for each generation)

Spermatogenic cell death

increased 300%

Sperm number

decreased 30%

Male infertility

approximately 10%

Comments

Avatar of: Dr.Raam, Shanthi

Dr.Raam, Shanthi

Posts: 43

September 25, 2007

A wonderful study to delve into the mechanics of how the environmental exposure to toxins affect across generations. I can see why the authors initially chose to use the endocrine "toxins" at a level much higher than normal. I wish they had added one group exposed to normal environmental level of these substances. Perhaps the study could be done at a variety of doses of toxins so as to understand the dose response. It is also time to explore effects of these same endocrine toxins in multiple animal species and effects of toxins other than endocrine toxins. Multi generational effects found in the orginal study may be restricted to endocrine toxins. This may not be true for environmental toxins which \naffect other organs of the body.

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