For estrogen replacement to provide stroke protection, it likely must be given soon after levels drop because of menopause or surgical removal of the ovaries, scientists report in the Journal of Neuroscience. Animal studies indicate a "critical period" for estrogen replacement and that when therapy is delayed, estrogen receptors on brain cells are significantly diminished along with the neuroprotection estrogen typically conveys, according to scientists from the Medical College of Georgia, North China Coal Medical University and the University of Texas Health Sciences Center at San Antonio. "We looked at the controversy over whether estrogen is going to be beneficial after long periods without it and found the answer appears to be 'no,'" says Dr. Darrell W. Brann, chief of MCG's Developmental Neurobiology Program and the study's corresponding author.
Link