Insulin signals in the back part of the liver help fat build up there when the mouse eats a high-fat diet.

Blocking insulin signals in the other part of the liver (pericentral zone) cuts down fat buildup in that area without raising blood sugar, even when the mouse eats a high-fat diet.

When the part of the liver that usually responds to insulin is blocked, the liver makes less fat even when the mouse eats a high-fat diet—but its blood sugar and insulin go up instead.

Turning off insulin signals in the back part of the liver doesn’t make blood sugar go up, even when the mouse eats a high-fat diet.

The front part of the liver needs insulin to make fat when the mouse eats a lot of fat—without it, fat production drops.

The front part of the liver needs insulin to handle sugar properly when eating a high-fat diet—without it, blood sugar rises.