Estrogen Has Protective 'Brain Effect'

U.S. researchers and Chinese researchers say rat studies show losing estrogen can lead to diminished brain function.

The study, published in the Journal of Neuroscience, found areas of the brain -- such as CA3 -- that tend to be stroke resistant and important in learning and memory, became vulnerable to stroke in rats that went without estrogen for long periods. It appears estrogen helps suppress free radical production that can become deadly to cells at higher levels.

"Estrogen must be doing something that is very critical for the protection of CA3 and we think it's suppressing NADPH oxidase production," Dr. Darrell W. Brann, chief of Medical College of Georgia who was the study's corresponding author, said in a statement.

NADPH oxidase is the enzyme that makes the free radical superoxide, the researchers said.

"If this is also true in humans, just using surgical menopause as an example, most women would be fine unless they came upon a severe stress," Brann said.