In male lab rats, giving a steroid called dexamethasone for about two weeks raises their blood pressure because their blood vessels get tighter — not because their heart pumps harder.

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.

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.

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.