Progesterone’s double life

EMORY (US)—Twenty-five years ago neuroscientist Donald Stein began to suspect that women’s brains differed from men’s when it came to recovering from traumatic brain injuries. Specifically, Stein observed that female lab rats recovered more readily than males—thanks to progesterone.

Thus began Stein’s series of discoveries regarding the effect of progesterone following traumatic brain injury. He was one of the first to uncover the neuro-protective properties of progesterone in the laboratory.

“Most people at the time were saying, this is nuts,” says Stein, Asa G. Candler Professor of Emergency Medicine at Emory School of Medicine and director of the department’s Brain Research Laboratory. “But we learned that progesterone is not just a female hormone, it’s a male hormone as well.”

Although widely considered a “sex steroid,” progesterone is naturally present in small but measurable amounts in the brains of males and females. Human brain tissue is loaded with progesterone receptors. Laboratory studies suggest that progesterone is critical for the normal development of neurons in the brain and exerts protective effects on damaged brain tissue.

Earlier this year, Emory University officials announced the third phase of a study to evaluate the effectiveness of the hormone progesterone on patients with acute traumatic brain injuries.

The multicenter, randomized, double-blinded study will enroll 1,140 patients at 17 medical centers in 15 states. Atlanta’s Grady Memorial Hospital will serve as the lead center, led by Emory University School of Medicine faculty researchers, in concert with colleagues from the Morehouse School of Medicine.

Emory researchers concluded in an earlier clinical trial that giving progesterone to trauma victims shortly following brain injury appears to be safe and may reduce the risk of death and long-term disability. Their three-year study, called ProTECT, enrolled 100 participants and was designed to evaluate whether progesterone can be administered intravenously in a safe and reliable way.

By expanding their testing in a large, nationwide study, the researchers hope to confirm these preliminary findings and determine if progesterone benefits victims of acute traumatic brain injury.

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