Environmental oestrogen shown to affect sperm
Date: 04-Jul-02
Country: AUSTRIA
Professor Lynn Fraser of Kings College in London told a fertility conference this week that a laboratory study on mice sperm showed the oestrogens stimulate sperm which has an impact on their ability to fertilise a female egg.
"They stimulate but they don't regulate," Fraser said in an interview.
"That could be a problem inside the female because if the sperm peak too soon and then an egg comes into view they will not be able to fertilise it."
Although the research was done on mice, Fraser and her colleagues believe oestrogens, hormones that develop and maintain female characteristics in the body, could have the same impact on human sperm.
Scientist suspect that exposure to environmental oestrogens and an increase in testicular cancer could be contributing to male infertility.
Environmental oestrogens are compounds found in soya, hops, paints, solvents, pesticides, herbicides and other industrial products and natural oestrogens are found are in the body.
Fraser and her team studied the impact of three environmental oestrogens and a natural oestrogen on the mice sperm.
The environmental oestrogens had a bigger impact on the sperm's ability to function than the natural oestrogen. Although the environmental oestrogens were 1,000 times less biologically potent than their natural counterpart, they could be 100 times more potent in sperm.
"At first sight these results suggest that oestrogens, particularly those found in the environment, could help fertility. However, the responses we have seen could have negative effects over time," Fraser told the European Society of Human Reproduction and Embryology (ESHRE) meeting in Vienna.
The scientists studied the impact of each individual compound but in real life sperm are exposed to many combinations of low concentrations of oestrogens.
"It is the first demonstration that these compounds have a direct effect on sperm fertility. No one has ever done that before. It means we need to look more carefully to see if ultimately this is a good or bad thing," Fraser said.
"Anything that affects sperm is going to have an effect on fertility."
About one in six couples worldwide experience an infertility problem. About 40 percent of cases are linked to men and 40 percent to women. The remainder are due to a joint problem.
Many of the world's top fertility experts are attending the four-day ESHRE meeting which highlights the latest advancements and techniques in reproductive medicine.