Giving a specific hormone called adrenomedullin to mice makes their bodies less able to use insulin properly—just like what happens in obesity—even though the mice don’t gain weight. This suggests the hormone alone might cause the problem.

When scientists block a specific protein in the blood vessels of overweight mice, their bodies get better at using insulin — which might mean we could one day treat type 2 diabetes in obese people by targeting the same protein.

When people or mice are obese, they have more of a substance called adrenomedullin in their blood, and this might stop their blood vessels from responding properly to insulin, which could be one reason why obesity leads to insulin problems in blood vessels.

In mice that are overweight, turning off a specific receptor in their blood vessels helps their muscles get more blood when insulin is present, which might mean blocking this receptor could help the body respond better to insulin.