Navigation Links
Environmental chemical cocktail may sabotage sperm

New research has shown that combinations of chemicals found in everyday products and food have subtle but potentially damaging effects on sperm fertility.

Professor Lynn Fraser told the 21st annual conference of the European Society of Human Reproduction and Embryology today (Wednesday), that her previous research had shown that certain chemicals known to mimic the female sex hormone, oestrogen, could individually affect the correct functioning of mouse sperm, but now her new research showed that when the chemicals were combined they had an even stronger effect. In addition, when she tested one chemical, genistein (found in soya and legumes), on human sperm, she found that the human sperm were much more sensitive to it than mouse sperm. Even tiny doses could cause human sperm to "burn out" and lose fertility.

Prof Fraser, who is Professor of Reproductive Biology at King's College London, said: "Given that these environmental oestrogenic xenobiotics [chemicals] are effective at very low concentrations, with combinations of compounds being even more potent, these results could have important negative implications for human fertility for two reasons. Firstly, humans are likely to be exposed to more than one such compound at any given time and, secondly, our results show that human sperm are even more sensitive to these compounds than mouse sperm."

Prof Fraser and her team tested combinations of three chemicals: genistein, 8-prenylnaringenin which is found in hops, and nonylphenol which is found in industrial products such as paints, herbicides and pesticides, cleaning products and in the production of pulp paper and textiles. They investigated the effect the chemicals had on capacitation, the stage when a sperm acquires the ability to fertilise an egg.

"We found that combinations of small quantities of these three xenobiotics stimulated sperm far more than when used individually," she said. In particular, the chemicals stimulated the sper m to undergo an acrosome reaction. This is when the cap on the head of the sperm ruptures and releases enzymes that enable the sperm to penetrate the coverings of the egg. If the acrosome reaction happens before a sperm reaches the egg, then fertilisation is unable to take place because the sperm has lost special "docking" molecules that allow it to bind to the egg.

Prof Fraser said: "Human sperm proved to be even more responsive than mouse sperm to genistein. These compounds are classified as environmental oestrogens, but they are very weak, so normally you would expect them to have to be in concentrations around 1,000 times stronger to get a response similar to that prompted by the naturally occurring oestrogen, oestradiol. Yet human sperm are responding to very low concentrations ?well within the amounts that have been measured in people's blood.

"At a time when there are concerns that the incidence of infertility may be rising, this research flags up important warning signs. Very little is currently known about the control of sperm function, especially in the body rather than in the laboratory, but the sensitivity of human sperm to these chemicals means that further investigations should be carried out to determine whether such environmental compounds might contribute to a decrease in human fertility. Other scientists have investigated the negative impact of environmental chemicals on testis function, resulting in reduced numbers of sperm being produced, but these effects require much larger doses than we have used. As far as I am aware, we are the only group looking at subtle effects that could have a serious impact on fertility without reducing the number of sperm being produced."

The mechanism of action of the environmental oestrogens was still not clear, but the researchers discovered that both genistein and nonylphenol significantly stimulated the production of cyclic AMP ?a chemical messenger, produced within the cell after external compounds have acted on the cell, that prompts an appropriate response. In the case of sperm, increased cAMP production appeared to stimulate premature sperm capacitation. "The sperm were still alive and their ability to move was unaffected, but the spontaneous acrosome reaction meant that they were unable to fertilise an egg," said Prof Fraser.

She said that the chemicals were more likely to affect sperm when they reached the female tract where they would be preparing to fertilise eggs. "Maternal exposure to the compounds is probably more important than paternal exposure. Given the likelihood that all of us are exposed to several xenobiotics at any one time, with soya in the diet and exposure to other compounds coming from plastics etc, we need to investigate their possible effects on the fertility of human sperm as quickly as possible."


Source:European Society for Human Reproduction and Embryology

Related biology news :

1. Environmental lessons from tsunami as worlds coastal population doubles
2. Environmental tobacco smoke linked to behavior problems in children and pre-teens
3. Environmental metagenomics diagnosing extreme environments, tapping opportunities for clean energy
4. Environmental toxins may cause bodys defenses to worsen lung disease
5. BRCA1 causes ovarian cancer through indirect, biochemical route
6. Study shows nanoshells ideal as chemical nanosensors
7. MSI releases moleculizer - a new approach to simulation of intracellular biochemical networks
8. Researchers discover chemical compounds that affect plant growth
9. Harmful chemicals may reprogram gene response to estrogen
10. Disease diagnosis, biodefense among UH chemical research projects
11. NYU and MSKCC research provides model for understanding chemically induced cancer initiation
Post Your Comments:

(Date:11/26/2015)... Research and Markets ( ) has announced the ... and Patent Infringement Risk Analysis" report to their ... Fingerprint sensors using capacitive technology represent a fast ... Idex forecasts an increase of 360% of the number ... the fingerprint sensor market between 2014 and 2017 (source ...
(Date:11/20/2015)... 2015 NXTD ) ("NXT-ID" or ... growing mobile commerce market and creator of the Wocket® ... was recently interviewed on The RedChip Money Report ... weekend on Bloomberg Europe , Bloomberg Asia, Bloomberg ... NXTD ) ("NXT-ID" or the "Company"), a biometric ...
(Date:11/19/2015)... Calif. , Nov. 19, 2015  Based on ... Frost & Sullivan recognizes BIO-key with the 2015 Global ... Each year, Frost & Sullivan presents this award to ... line catering to the needs of the market it ... product line meets and expands on customer base demands, ...
Breaking Biology News(10 mins):
(Date:11/27/2015)... 2015 --> ... companion diagnostics is one of the major ... pharmaceutical companies and diagnostic manufacturers working together ... . --> ... global cancer biomarkers market spread across 89 ...
(Date:11/26/2015)... November 26, 2015 ... Accutest Research Laboratories, a leading ... Organization (CRO), has formed a strategic ... - Temple Health for joint work ... (Photo: ) , --> ...
(Date:11/26/2015)... 26, 2015 --> ... in imaging technologies, announced today that it has received a ... the Horizon 2020 European Union Framework Programme for Research and ... trial in breast cancer. , --> ... --> --> The study aims to ...
(Date:11/25/2015)... , November 26, 2015 ... Global Biobanking Market 2016 - 2020 report analyzes ... maintaining integrity and quality in long-term samples, minimizing ... long-term cost-effectiveness. Automation minimizes manual errors such as ... technical efficiency. Further, it plays a vital role ...
Breaking Biology Technology: