Glucose metabolism begins with glycolysis, in which the molecule is broken down into pyruvate in ten enzymatic steps. A significant proportion of pyruvate is converted into<unk> ctate (usually 10:1). The human metabolism produces about 20 mmol/kg of<unk> ctic acid every 24 hours. This happens predominantly in tissues (especially muscle) that have high levels of the "A" isoform of the enzyme<unk> ctate dehydrogenase (LDHA), which predominantly converts pyruvate into<unk> ctate. The<unk> ctate is carried by the bloodstream to other tissues where it is converted at the expense of ATP back to pyruvate by the "B" isoform of LDH (LDHB). Firstly there is gluconeogenesis in the liver (as well as the kidney and some other tissues), where pyruvate is converted into glucose; this is known as the Cori cycle. In addition,<unk> ctate moved to other tissues enters the citric acid cycle and eventually oxidative phosphorylation, a process that yields ATP. Elevations in<unk> ctate are either a consequence of increased production or of decreased metabolism. With regards to metabolism, this predominantly takes place in the liver (70%), which explains that<unk> ctate levels may be elevated in the setting of liver disease. In "type A"<unk> , the production of<unk> ctate is attributable to insufficient oxygen for aerobic metabolism. If there is no oxygen available for the parts of the glucose metabolism that require oxygen (citric acid cycle and oxidative phosphorylation), excess pyruvate will be converted in excess<unk> ctate. In "type B"<unk>  the<unk> ctate accumulates because there is a mismatch between glycolysis activity and the remainder of glucose metabolism. Examples are situations where the sympathetic nervous system is highly active (e.g. severe asthma). There is controversy as to whether elevated<unk> ctate in acute illness can be attributed to tissue hypoxia; there is limited empirical support for this theoretical notion.
Lactic acidosis
Metabolic acidosis
Acidosis
Metabolic alkalosis
Azotemia
Hyperammonemia
Alkalosis
Hypercapnia