Female Egg Production

[Guest guest]

While this isn't strictly about nutrition, it is interesting ... seems that

maybe women keep producing eggs throughout their lives, so " menopause "

isn't just " running out of eggs " .

-- Heidi Jean

http://www.washingtonpost.com/wp-dyn/articles/A48074-2004Mar10.html?referrer=ema\

il

For one thing, Tilly said, " it makes no sense to have a fixed population of eggs

that have to sit around for decades until they are used, " accumulating mutations

and other problems along the way. In less complex animals, including insects,

females as well as males make sex cells into adulthood. It is gratifying, Tilly

said, to see mice following that sensible pattern.

In one set of tests, Tilly's group showed that on a single day as many as 1,200

egg-encasing follicles were dying in the ovaries of young adult mice -- far too

many for the initial supply to last a reproductive lifetime. The group also

identified a population of what appear to be egg stem cells -- the

self-replenishing kind of cell that makes egg cells -- in one region of the

ovary. Each ovary seems to have about 63 such cells -- few enough to have been

missed by early ovary gazers.

Another experiment showed that meiosis, a process unique to the production of

sperm and eggs, was occurring in the ovaries of adult mice. The team also used

molecular markers to show that some stem cells in adult mouse ovaries seemed to

be growing into new eggs.

For one strain of mouse, the team calculated that about 77 new eggs are produced

every day -- not a huge number, but infinitely bigger than zero.