When scientists make rat muscle cells produce more of a specific protein called PP-1G, the cells respond to insulin more strongly—boosting both the activity of a key enzyme and the pump that moves salt in and out of the cell.

When rats are given insulin, a specific part of a pump in their muscle cells moves from inside the cell to the outer membrane, but another similar part stays where it is.

In rat muscle cells, a very small amount of a chemical called okadaic acid — which blocks one specific enzyme — doesn’t stop insulin from activating a pump that moves salt in and out of the cell, and it also doesn’t change how that pump gets turned on or off.

When you eat, your body releases insulin, which helps muscle cells pull more potassium from your blood by putting more pumps on their surface—this keeps your muscles working smoothly after meals.

When insulin is present in rat muscle cells, it makes a special pump work harder to move salt in and out of the cells—but if you block certain cleanup enzymes in the cell, the pump doesn’t speed up anymore, which suggests insulin uses those enzymes to turn the pump on.

When rats are given insulin, a specific part of a pump in their muscle cells (called the beta 1 subunit) becomes more active and shows up more in the cell’s outer layer, but another similar part (beta 2) stays the same.