麻豆传媒

DUTCH researchers have identified a hormone that may influence how quickly
mammals use up their lifetime鈥檚 supply of eggs. The hormone might one day be
used to delay menopause to prevent conditions such as osteoporosis, or to extend
a woman鈥檚 fertile life.

Axel Themmen and his colleagues at Erasmus University in Rotterdam were
studying mice when they found that the substance, called anti-M眉llerian
hormone (AMH), puts the brakes on the early stages of follicle development.

At one week old, baby mice have thousands of primordial follicles that are
capable of developing into eggs. Over a mouse鈥檚 lifetime, most of those
follicles will start to develop. But whereas a few will go all the way and
become mature eggs, the vast majority will die off before reaching that
stage.

AMH is best known for its role in male embryo development, but is also made
by the granulosa cells that surround the growing follicles. This suggests that
AMH helps keep the number of developing follicles at a constant level, says
Themmen.

At four months old, mice that lacked AMH had 3 times the number of growing
follicles and fewer primordial follicles than normal mice, Themmen told the 11th
International Congress of Endocrinology in Sydney last week. But the mice that
lacked the AMH brake used up their eggs quicker. Because there were no
primordial follicles left in 13-month-old mice, says Themmen, there were no
small growing follicles.

If AMH inhibits the development of follicles in humans in the same way, it
may be possible to use it as a drug to delay the menopause, says Ray Rodgers, a
reproductive endocrinologist at Flinders University in Adelaide. 鈥淚f we could
make the reservoir of primordial follicles last until the end of a woman鈥檚 life,
we may be able to prevent menopause, and the osteoporosis and cardiovascular
changes that follow,鈥� he says.

Inhibiting the follicle development could even help extend a woman鈥檚
reproductive life by preventing eggs being used up during periods when she
doesn鈥檛 want to conceive, Rodgers speculates.