By Kendra Snyder and Diane Greenberg
The Society for Neuroscience has selected recent research on estrogen and its effect on behavior conducted at the U.S. Department of Energy’s Brookhaven National Laboratory for its “hot topics” book distributed to reporters attending the society’s 2011 meeting in Washington, D.C., November 12-16.
“The abstract I submitted was one of under 200 chosen from 16,000 abstracts,” said Anat Biegon, a senior medical scientist at Brookhaven Lab. “I think the research is of general interest because for the first time, we’ve shown that the human brain’s capacity for making estrogen is linked to the ability to control and inhibit behavior — particularly risky, potentially dangerous behavior. This data could lead to new treatments for addiction and anti-social behavior.”
The Society for Neuroscience meeting is the largest forum for neuroscientists to debut their research and network with colleagues around the world. Biegon gave a poster presentation on her work at the meeting on November 14.
Inhibitory control of behavior, or constraint, is an important modulator of an individual’s ability to refrain from habits and behaviors harmful to themselves and others. Large population studies have indicated that on average, women have higher scores on personality tests measuring constraint when compared to men, suggesting an involvement of sex hormones. While the main source of estrogen in the blood of women is the ovaries, the Brookhaven researchers recently found that both men and women can make estrogen in a brain region called the amygdala, which is important in the control of emotions.
To further investigate these relationships, the Brookhaven researchers used a brain-scanning technique called positron emission tomography (PET) to examine estrogen-synthesizing capacity in the human brain. An enzyme called aromatase produces estrogen, and the researchers measured the availability of this enzyme in the brain by using a radioactively tagged drug — vorozole — known to bind tightly to aromatase and inhibit its activity. A group of 30 healthy adult men and women were first asked to complete a personality questionnaire and their constraint score was calculated. Subsequently, they were injected with the tagged vorozole to image the availability of aromatase in their amygdala.
The researchers found that the availability of the estrogen-synthesizing enzyme was positively linked with the group’s constraint scores, meaning that those who scored high on constraint also had high availability of aromatase in their amygdala. When the analysis was done separately in men and women, the researchers discovered that the link is stronger in women.
Knowledge of sex differences and sex hormone involvement in the ability to inhibit behavior provides insight into basic mechanisms related to anti-social behaviors and addictions. The researchers’ results suggest that estrogen production within the brain is important in inhibitory control and may provide novel targets for treatment or prevention in these disorders.
2011-2698 INT/EXT | Media & Communications Office
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