X-Message-Number: 12448
Date: Tue, 21 Sep 1999 18:18:41 -0400
From: Jan Coetzee <>
Subject: Hormones Hold One Key To Aging

Hormones Hold One Key To Aging, U.S. Study Finds

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - Stress hormones could hold one big key to staying
sharp in old age,
researchers said Monday.

Tests on rats showed that blocking stress hormones revved up the
production of brain cells in a
part of the brain, the hippocampus, which is important in memory, Ronald
McKay and Heather
Cameron of the National Institute of Neurological Disorders and Stroke
(NINDS) said.

Writing in the journal Nature Neuroscience, they said their study may
eventually lead to a drug
that could help people become less forgetful as they get older.

Several studies have shown that stress hormones -- specifically
corticosteroids -- are linked with
memory loss. And corticosteroid levels are known to go up as people age.

``Older people, they are kind of forgetful,'' McKay said in a telephone
interview.

``But there is a group that seems to have memory loss because of high
stress hormones. The
memory loss they show is hippocampal. This set us to wondering.''

McKay's team also knew that one of the few places in the brain where
cells keep growing is in
the dentate gyrus, the doorway into the hippocampus.

``Although neurons are replaced in the dentate gyrus, this gets slower
as animals get older. We
wondered if the explanation could be entirely elevated
corticosteroids.''

So they took away the hormones in old rats, by cutting out their adrenal
glands, which produce
corticosteroids. Then they looked at their brains.

``When we take out the adrenal glands in the rats, the rate of neuron
replacement goes way up,''
McKay said. ``It's not that we get a little effect -- we get a huge
effect.''

It is not possible to do the same in people. The adrenal glands are
extremely important, and
corticosteroids control the functions of many organs.

``Stress hormones are actually good for you,'' McKay said. ''As you get
older, they are probably
doing all kinds of beneficial things for you.''

People whose adrenal glands do not work properly develop Addison's
disease, for instance --
which starts with dizziness and is marked by very low blood sugar, an
inability to fight of
infection, weak muscles and other symptoms.

But McKay said it might be possible to develop a drug that could block
the ``bad'' effects of
corticosteroids in the brain while allowing the good effects to
continue. It might be similar to
breast cancer drugs that block the cancer-promoting effects of estrogen
while allowing the
beneficial effects that keep women healthy, he said

``If you could develop a drug that would block corticosteroid action,
even if it took some time
and some expense, it would be rather cool because it is a reversible
effect,'' McKay said.

First, scientists need to see if the effects of corticosteroids are
similar in humans.

McKay's team did not look at the behavior of their rats, to see if their
memories actually
improved.

Instead, he said he was hoping to look at people who have been given
corticosteroids as drugs.
``One effect of publishing this study is that I was hoping to get phone
calls from people testing
people who are being treated with corticosteroids for one reason or
another,'' McKay said.

He would like to measure their memory function.

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