Something in female sex chromosomes appears to trigger a rise in blood pressure after the onset of menopause, says a study by Georgetown University Medical Center (GUMC) scientists.
The finding challenges the current belief that sex hormones are largely responsible for regulating blood pressure.
Published in Hypertension, the research is the first of its kind and involves male mice engineered to have female (XX) sex chromosomes, and female mice with male (XY) chromosomes.
The finding suggests that sex chromosomes regulate blood pressure in and of themselves. Most researchers have thought that sex hormones (estrogen and testosterone) play key roles in controlling blood pressure and that women develop hypertension after reaching menopause because of loss of estrogen.
"Up until now, it has been impossible to separate the influence of sex chromosomes from the effects of sex hormones, and in this paper, we have shown for the first time that sex chromosomes are impacting blood pressure - independent of sex hormones," says the study's lead investigator, Kathryn Sandberg, PhD, director of the GUMC Center for the Study of Sex Differences in Health, Aging, and Disease.
"That is not to say sex hormones don't matter in blood pressure regulation, because they do, but we now know they aren't the only players," she says. "Estrogen likely works to protect against hypertension, but once the hormone is depleted, something is unmasked on female XX chromosomes that allows blood pressure to rise."