Where does most (70-80%) of the whole-body hypokalemic response to insulin occur?

The correct answer is that most (70-80%) of the whole-body hypokalemic response to insulin occurs in the skeletal muscle. Insulin facilitates the uptake of glucose and electrolytes, including potassium, into cells, particularly in skeletal muscle tissue. This effect is enhanced in the postprandial state, where insulin levels rise to help reduce blood glucose levels by promoting cellular uptake of glucose and potassium.

Skeletal muscle demonstrates a significant capacity and responsiveness to insulin's effects, which is critical for maintaining potassium homeostasis. When insulin is secreted, it binds to receptors on skeletal muscle cells, triggering a series of biochemical reactions that enhance the activity of sodium-potassium ATPase pumps. This action effectively pulls potassium from the extracellular space into the cells, thus reducing serum potassium levels and contributing to the hypokalemic response.

The liver and kidneys also play roles in potassium metabolism, but they do not account for the predominant share of insulin-induced hypokalemia as observed in skeletal muscle. The spleen is not typically involved in this metabolic response, making it irrelevant in the context of insulin's effects on potassium levels. Understanding the specific pathways and tissues involved helps clarify how insulin influences potassium dynamics in the body.