Why does a steroid make blood pressure go up in rats?
Hemodynamics of dexamethasone-induced hypertension in the rat
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
A medicine called dexamethasone made rats' blood pressure go up by making blood vessels stiffer, not by making the heart pump harder. Giving another medicine to relax blood vessels didn't fix the high blood pressure, which is surprising.
Surprising Findings
Minoxidil successfully lowered blood vessel resistance but did not reduce blood pressure in steroid-treated rats.
This contradicts the standard medical model that high blood pressure is primarily caused by high resistance. If lowering resistance doesn’t fix it, other factors—like increased fluid volume or vascular stiffness—may be at play.
Practical Takeaways
If you’re on long-term steroids, don’t assume standard blood pressure meds that relax blood vessels will fully protect you.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
A medicine called dexamethasone made rats' blood pressure go up by making blood vessels stiffer, not by making the heart pump harder. Giving another medicine to relax blood vessels didn't fix the high blood pressure, which is surprising.
Surprising Findings
Minoxidil successfully lowered blood vessel resistance but did not reduce blood pressure in steroid-treated rats.
This contradicts the standard medical model that high blood pressure is primarily caused by high resistance. If lowering resistance doesn’t fix it, other factors—like increased fluid volume or vascular stiffness—may be at play.
Practical Takeaways
If you’re on long-term steroids, don’t assume standard blood pressure meds that relax blood vessels will fully protect you.
Publication
Journal
Hypertension Research
Year
2009
Authors
Sharon L. H. Ong, Yi Zhang, M. Sutton, J. Whitworth
Related Content
Claims (6)
Your blood pressure goes up if your heart pumps more blood, if you have more blood in your body, or if your blood vessels become tighter — any one of these can push pressure higher.
In male lab rats given a drug that raises blood pressure, the overall increase in blood vessel resistance isn't due to major changes in key organ areas — so the problem might be spread across many tiny, unmeasured blood vessels instead.
In male lab rats, taking minoxidil and dexamethasone together lowers blood vessel resistance and boosts heart performance, but it doesn’t stop blood pressure from going up — meaning just relaxing blood vessels might not be enough to fix steroid-linked high blood pressure.
Giving male lab rats a specific dose of a steroid called dexamethasone for about two weeks slows down their weight gain and shrinks their thymus gland, which shows the drug is having a strong effect on their body even if they don’t lose weight overall.
In male lab rats with high blood pressure caused by a steroid, taking a drug called minoxidil seems to make their hearts pump more blood with each beat—without changing how fast the heart beats—meaning the heart might be filling better or squeezing harder.