Infertile growth

methoxychlor (mxc), a common pesticide used on food crops, may reduce fertility in women, claim researchers at the Yale School of Medicine, the us. They found mxc suppressed expression of Hoxa10 -- an oestrogen-regulated gene -- by up to 70 per cent, thereby reducing the ability of the uterus to support pregnancy. The researchers used mice and human cell lines to confirm their findings that appear in Endocrinology (Vol 146, No 8, August 2005).

Previous research with mxc and other chemicals like ddt had shown they induce abnormalities in tissue development and function in the female reproductive tract.
Considered a safer replacement for ddt, mxc is applied directly to food crops, livestock, home gardens and pets. But it is an endocrine disruptor and interferes with the action of hormones that suppress gene expression and subsequently affect reproductive tract development. "Alterations in gene expressions may be detected in the foetus or newborn, whereas changes in the functioning of reproductive organs may only become apparent upon sexual maturation," says lead author Xiaolan Fei.

Though the impact of mxc exposure in humans is not well known, it may show effects similar to diethylstilbestrol (des) -- a synthetic oestrogen. " mxc has an adverse effect on mice similar to that of des," said Hugh S Taylor of Yale School of Medicine. Because mxc and des have similar effects on developmental gene expression in exposed animals, the effect of human exposure to either of these two endocrine disruptors may also be similar, the study concludes.