Sodium-potassium-ATPase, also called "pump", is a crucial enzyme responsible for transporting sodium (Na+) and potassium (K+) ions across the cell membrane. The terms "pump" and "enzyme" are often used interchangeably. The pump is present in the plasma membrane of all animal cells and maintains a much higher concentration of potassium (and a much lower concentration of sodium) in the cytoplasm than exists outside the cell. This cation transport system is essential for cell function and plays a central role in the Na+/K+ balance of virtually all animals. Movements of ions into and out of cells form the basis for the transmission of signals in the brain and heart as well as other tissues of the body that allow all animals to breathe, move, think, digest food, and pretty much function in all respects. Most ion pumps transport different kinds of ions in opposite directions across cell membranes. The Akita and Shiba Inu have erythrocytes with high potassium and low sodium concentrations due to retention of Na, K-ATPase in mature erythrocytes. This disorder is inherited as autosomal recessive trait. Some dogs have an increased concentration of reduced glutathione, which protects the cells against oxidative damage.3
Potassium is essential for the proper functioning of the heart, kidneys, muscles, nerves, and digestive system. Usually the food supplies all of the potassium needed. However, certain diseases, such as kidney disease and gastrointestinal disease with vomiting and diarrhea, and drugs remove potassium from the body. Hyperthyroidism gives rise to an increase in pump activity, while hypothyroidism results in its decreased activity. Lack of magnesium can also lead to accumulation of intracellular sodium and loss of intracellular potassium. The sodium-potassium pump high activity is believed to underlie high blood pressure and it is the target of digoxin.
- Maria E. Everts. Potassium homeostasis during exercise in domestic species: the role of the sodium-potassium pump in skeletal muscle
- Deadly Coral Toxin Exposes Ion Pump's Deepest Secret. ScienceDaily (Jan. 27, 2003)
- Mary Anna Thrall, Dale C. Baker. Veterinary hematology and clinical chemistry