When scientists turned off insulin's signal in the kidney tubes of obese, insulin-resistant mice, the mice didn't hold onto salt as much — showing that insulin in the kidneys helps control salt balance in obesity.

In mice on a high-fat diet, turning off insulin's signal in the kidney doesn't change blood pressure or salt balance — meaning insulin in the kidney might not be needed to hold onto salt when obesity is caused just by diet.

When scientists turned off insulin's signal in the kidneys of obese, insulin-resistant mice on a certain hormone, the mice started spilling a lot of sugar in their urine—way more than normal—showing that insulin in the kidneys helps control how much sugar gets reabsorbed.

Mice on a high-fat diet hold onto more salt because their kidneys are reabsorbing more of it through a specific pathway—this was shown by giving them a water pill and seeing they flushed out way more salt than mice on a low-fat diet.

Insulin makes your kidneys hold onto salt, even if you're not eating much of it.

In mice with obesity and high blood pressure caused by a hormone called fludrocortisone, turning off the insulin receptor in the kidney's tubules only slightly lowers blood pressure—by about 2.3 points—suggesting insulin in the kidneys plays a small role in raising blood pressure here.