When women who are healthy and not menopausal eat a lot more salt for 10 days, their kidneys release more of a substance called endothelin-1 to help flush out the extra salt—but men’s kidneys don’t do this same thing.

Women’s kidneys respond to eating a lot of salt by making more endothelin-1—a substance that helps flush out salt—but men’s kidneys don’t make more of it, even when they eat the same amount.

In rats, male kidneys make more endothelin-1 when they eat salt—but in humans, it’s the opposite: female kidneys make more. This shows we can’t just assume animal results apply to people.

When people who don’t get high blood pressure from salt eat more or less salt, their kidneys adjust how much salt they pee out—no matter if they’re male or female.

When mice with lupus eat a lot of salt, their kidneys release more of a chemical called endothelin-1, but they also make less of the receptor that makes blood vessels tighten — which might help protect their blood pressure.