LACTATE

 

Introduction: During power exercises such as sprinting, when the rate of demand for energy is high, glucose is broken down and oxidized to pyruvate, and lactate is then produced from the pyruvate faster than the body can process it, causing lactate concentrations to rise. The production of lactate is beneficial because it regenerates NAD+ (pyruvate is reduced to lactate while NADH is oxidized to NAD+), which is used up in oxidation of glyceraldehyde 3-phosphate during production of pyruvate from glucose, and this ensures that energy production is maintained and exercise can continue.  

During intense exercise, the respiratory chain cannot keep up with the amount of hydrogen atoms that join to form NADH, and cannot regenerate NAD+ quickly enough. The resulting lactate can be used in these ways: 

(1) Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells. 

(2) Pyruvate is then directly used to fuel the citric acid cycle. 

(3) Conversion to glucose via gluconeogenesis in the liver and release back into circulation via the Cori cycle If blood glucose concentrations are high, the glucose can be used to build up the liver's glycogen stores. 

RELATED.

1.  Glycogen

2.  Insulin

3.  Glycolysis

4.  Biochemistry