Insulin forces which of the following electrolytes out of the plasma and into the cells?
A. Calcium
B. Magnesium
C. Phosphorus
D. Potassium
Correct Answer: D. Potassium
Insulin forces potassium out of the plasma, back into the cells, causing hypokalemia. Potassium is needed to help transport glucose and insulin into the cells. Insulin shifts potassium into cells by stimulating the activity of Na+-H+ antiporter on cell membrane, promoting the entry of sodium into cells, which leads to activation of the Na+-K+ ATPase, causing an electrogenic influx of potassium. IV insulin leads to a dose-dependent decline in serum potassium levels
Option A: When levels of blood sugar, or glucose, rise, it is efficiently taken up by beta-cells. Within the cells, glucose initiates a chain of molecular events that lead to calcium channel opening, allowing more calcium ions to flow into the beta-cells. Calcium ions stimulate insulin release to the blood.
Option B: Magnesium has an important role in insulin action, and insulin stimulates magnesium uptake in insulin-sensitive tissues. Impaired biological responses to insulin are referred to as insulin resistance.
Option C: A rise in insulin causes phosphate to move to the intracellular compartment. Additionally, the increased anabolism leads to the formation of high-energy phosphate bonds, further depleting phosphate levels.
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