Laktatet

Laktatet is the physiological term for lactate, the conjugate base of lactic acid. In mammals, lactate is produced mainly in tissues during glycolysis when oxygen availability is limited. The conversion of pyruvate to lactate is catalyzed by lactate dehydrogenase (LDH) and serves to regenerate NAD+, allowing glycolysis to continue and providing a rapid source of ATP.

Lactate exists primarily as the L-enantiomer in human biology, and it is transported across cell membranes by monocarboxylate transporters (MCT1 and MCT4, among others). Through the lactate shuttle, lactate produced in one tissue can be taken up and oxidized in another, including heart, brain, and liver. In the liver and kidneys, lactate can be converted back to glucose via gluconeogenesis in the Cori cycle.

In normal breathing and exercise, lactate levels stay within a range; during intense exercise or insufficient oxygen, lactate accumulates in blood. Clinically, blood lactate concentration is used as a marker of tissue hypoxia or metabolic stress; typical resting levels are around 0.5–2.0 mmol/L, with higher readings indicating stress or impaired clearance. Severe lactic acidosis can occur in critical illness due to inadequate perfusion or metabolism.

Laktatet is also related to fermentation processes, where lactic acid bacteria produce lactate in foods. The concept and measurement of lactate are central to exercise physiology, critical care, and metabolic research.