From the Science & Technology Desk Published 10/27/2002 6:05 PM

TUCSON, Ariz., Oct. 27 (UPI) -- If postmenopausal women suffering from Alzheimer's disease continue to take estrogen, it actually could worsen their memory loss, a new animal study released Sunday suggests.

Although the study looked at 40 female rats to determine the effects of routine estrogen replacement therapy on cognition, the findings could have implications for humans, researchers said.

Led by Gary Wenk of the University of Arizona at Tucson, the team surgically removed the ovaries of rats to induce menopause. The loss of the ovaries also affected the hypothalamus, a key region in the brain, in ways that are similar to the changes that occur among menopausal women.

As described in the October issue of the journal Behavioral Neuroscience, the researchers then put the rats through a water maze test to measure their memory. They found the ovary removal was not enough to impair the animals' performance, but as soon as the rats were given either regular estrogen replacement therapy or induced chronic brain inflammation, the animals' water maze test scores worsened. Furthermore, the rats that received both procedures performed far worse than those receiving either estrogen alone or subjected to brain inflammation -- which simulated the effects of Alzheimer's.

"Those animals that had inflammation and were getting chronic estrogen therapy were doing the worst," Wenk told United Press International. "Were we surprised? I should say 'yes,' we were."

Estrogen long had been touted to be beneficial to memory, Wenk said. But a study published two years ago in the Journal of the American Medical Association suggested otherwise. Although postmenopausal women with mild-to-moderate Alzheimer's exhibited initial benefits from taking the hormone replacement therapy, the study stated, eventually they showed more decline than women taking an inactive placebo.

"Every decade has its magical drug and everyone takes it ... estrogen was something everyone was hanging their hats on," Wenk said. "In hindsight, it looked like we hung too much on it."

Dr. Philip J. LeFever, an associate professor of psychiatry at St. Louis University, said estrogen can aid the brain before the onset of Alzheimer's, but after the disease has begun, hormone replacement is not useful because it can stimulate cell growth at the wrong times.

"It could be protective, maybe in the beginning," LeFever told UPI. "Once a person has Alzheimer's disease, then I think things could change. A theory might be that once Alzheimer's starts, once you get the plaques (in the brain), once you get the tangles, maybe you get cell inflammation ... (and) once you stick estrogen on board, it may aggravate" those cells.

-- Anonymous, October 28, 2002