Reproductive effects of weed killer, glyphosate, examined in mice

Date:
July 28, 2020
Source:
Iowa State University
Summary:
A pair of recently published studies analyzed how ovarian function
in mice responded to various levels of exposure to glyphosate,
a chemical extensively used to kill weeds. The results showed
exposure changed the level of some ovarian proteins but did not
impact ovarian steroid production, an indication glyphosate may
not adversely affect reproduction.



FULL STORY ========================================================================== Exposure to the chemical glyphosate changed the level of some ovarian
proteins in mice but did not impact ovarian steroid production, an
indication glyphosate may not adversely affect reproduction, according
to a new study.


==========================================================================
Two studies, published in the peer-reviewed academic journals Toxicology
and Applied Pharmacology and Reproductive Toxicology, analyzed how
ovarian function in mice responded to various levels of exposure to
glyphosate, a chemical extensively used to kill weeds. The research
found the highest exposure levels included in the experiments resulted
in increased ovarian weight and follicle number, but Aileen Keating,
an associate professor of animal science at Iowa State University and
lead author, said the research did not uncover evidence that glyphosate
affects the healthy functioning of ovaries.

"The big takeaway is that while we did find some changes in ovarian
proteins, many of the endpoints we examined were not altered by glyphosate exposure," Keating said.

Keating, whose research focuses on reproductive health, said it's unclear
if the increased ovarian size or altered protein abundance that resulted
from the highest exposure level could cause changes in the ability of
mice to reproduce.

Answering that question will require further study, she said. The study
found glyphosate exposure did not affect heart, liver, spleen, kidney
or uterus weights. Keating said the study's conclusions largely agreed
with findings published years ago meant to determine how the chemical
can be used safely.

The researchers introduced glyphosate to groups of mice orally, mimicking
how humans could be exposed to glyphosate residue in water or in crops
used for food production. Groups of mice were exposed to different
glyphosate levels and for periods of 5, 10 or 20 weeks. The researchers
chose the doses, measured in milligrams per kilogram of bodyweight, to approximate potential glyphosate levels that humans could be exposed to.

However, Keating noted that it remains unclear how much glyphosate
humans are exposed to regularly, which made it difficult to judge
what levels were appropriate for the experiments. Additionally, they
used only the active compound contained in weed treatments, not the
additional ingredients.

The use of glyphosate has sparked controversy regarding its proposed
health effects. Accordingly, Keating said the researchers designed the
study to be as unbiased as possible. For instance, the scientists didn't
know the glyphosate treatment of individual samples as they conducted
their analysis, which meant perceived expectations or biases could not
affect the results.

"It's a commonly used chemical, and there's been some alarm in the
media about its use," she said. "We need more well designed, independent studies to see if this is something we should be concerned about."

========================================================================== Story Source: Materials provided by Iowa_State_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Shanthi Ganesan, Aileen F. Keating. Ovarian mitochondrial and
oxidative
stress proteins are altered by glyphosate exposure in
mice. Toxicology and Applied Pharmacology, 2020; 402: 115116 DOI:
10.1016/ j.taap.2020.115116 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200728121208.htm

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