Register for Possible Link Reported Between Female Testosterone and High Blood Pressure
HypertensionFebruary 8, 2001
2001 FEB 8 - (NewsRx.com & NewsRx.net) -- Female testosterone is a possible cause of high blood pressure in post-menopausal women, no matter whether they take hormone replacement.
That hypothesis is based on most recent findings in an ongoing study by Dr. Jane Reckelhoff, a scientist from the University of Mississippi Medical Center (UMC), in Jackson, who has been exploring gender differences in high blood pressure for a dozen years.
"I've learned a lot more lately about hypertension in post-menopausal women," Reckelhoff said. "We know that aging is associated with oxidative stress and we think testosterone works through that system."
Her findings also bring some new ideas about what post-menopausal women can do to possibly reduce the occurrence of hypertension.
Reckelhoff's ongoing study is funded in part by a five-year grant to UMC from the U.S. National Institutes of Health (NIH). She serves as an investigator for that project, titled "Cardiovascular Dynamics and Their Control" under UMC's Department of Physiology.
Men become hypertensive earlier and more frequently than women. But, after menopause, blood pressure in women goes up even more so than in men of the same age, Reckelhoff noted. Initially, scientists hypothesized that the estrogen depletion in aging women was the trigger, but that no longer is believed to be the cause. Women who take hormone replacement don't escape the increased incidence of hypertension, she said.
Testosterone may naturally increase in women as estrogen naturally decreases during menopause. Women have the same testosterone as found in men, but less than one-tenth as much, Reckelhoff said. Testosterone also is present in some hormone replacement drugs. "The only reason testosterone is included in that cocktail is to increase women's libido. A man clearly thought that up," Reckelhoff added, laughing.
"Testosterone either doesn't change with menopause or it increases - and we think there's some sensitivity to testosterone that develops," she said. "Data shows it takes 10 years for blood pressure to increase in post-menopausal women, so it doesn't look like estrogen" is the trigger.
"We think testosterone is working through some hormonal system, such as the intra-renal hormone system, to cause oxidative stress," Reckelhoff continued. "In the intra-renal hormone system, there is increased sodium absorption and a hormone produced in the kidney that constricts blood vessels - and we think testosterone is increasing that hormone," she explained. "The hormone itself is called angiotensin II, which also causes oxidative stress. Oxidative stress leads to constriction of the blood vessels and higher blood pressure.
"That's why they tell you to take vitamins E and C, because they are anti-oxidants and work against oxidative stress and the aging process," she noted.
Her study's control group included five types of white rats: normal males, castrated males, normal females, females with their ovaries removed, and females with their ovaries removed who had been given testosterone.
What they are discovering might significantly help curtail the incidence of high blood pressure in post-menopausal women some day.
"If this hypothesis is correct, one solution for post-menopausal women who take estrogen is to switch to hormone replacement drugs without testosterone."
This article was prepared by Women's Health Weekly editors from staff and other reports.
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