When scientists block a specific enzyme in rat muscle cells using a chemical called wortmannin, it stops insulin from making a pump (Na+/K+-ATPase) work better — like turning off a switch that normally helps the pump get activated.

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 insulin is added to rat muscle cells, it turns down a specific molecular switch (phosphorylation) by 60%, but if you add calyculin A, that switch stays on—though a weaker chemical called low-dose okadaic acid doesn’t stop it.

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.

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 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.