When insulin is added to rat leg muscle, it makes the muscle’s sodium-potassium pump work 23% harder, which lowers the sodium inside the cells by 27%—but it doesn’t create more pumps to do this job.

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 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.

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 present, it tells muscle cells to pump more sodium and potassium around, which creates a better environment for the cell to pull in more creatine — a compound that helps muscles store energy.

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.