Lactic acid accumulation

Sahlin, K., Edstrom, L., Sjoholm, H., Hultman, E. (1981). Effects of lactic acid accumulation and ATP decrease on muscle tension and relaxation. Am. J. Physiol. 240, C121-C126. 

Oxalic acid is poisonous to humans, but its concentrations are generally too low in foods to be of concern, although rhubarb leaves are quite poisonous. Lactic acid is produced from the fermentation of lactose, which is the principal sugar found in milk. The taste and smell of sour milk is due to the production of lactic acid from bacterial fermentation. Lactic acid accumulates in our muscles during exercise and strenuous physical activity. It is responsible for the sore, aching feeling often associated with these activities. Benzoic acid is the simplest aromatic carboxylic acid. 

This glucose may be released into the bloodstream and returned to the muscles. The overall process is known as the Con cycle. Lactic acid accumulates in muscle after vigorous exercise. It is exported to the liver slowly, but if mild exercise continues the lactate may be largely oxidized within muscle via the tricarboxylic acid cycle. Recent NMR studies have shown that lactic acid is formed rapidly during muscular contraction,... 

Deficiency of pyruvate dehydrogenase is the most frequent cause of lactic acidemia ac Since this enzyme has several components (Fig. 15-15), a number of forms of the disease have been observed. Patients are benefitted somewhat by a high-fat, low-carbohydrate diet. Transient lactic acidemia may result from infections or from heart failure. One treatment is to administer dichloroacetate, which stimulates increased activity of pyruvate dehydrogenase, while action is also taken to correct the underlying illness.d Another problem arises if a lactate transporter is defective so that lactic acid accumulates in muscles.6... 

Constant monitoring of both cells and medium is possible. However high levels of lactic acid accumulate at the high cell densities obtained and constant replenishment of the medium is essential together with use of a combination of Hepes and high bicarbonate to maintain the pH. 

Pyruvic acid is formed during the metabolism of glucose. During periods of strenuous exercise, when there is insufficient oxygen to metabolize pyruvic acid to CO2, pyruvic acid is reduced to lactic acid. The tired feeling of sore muscles is a result of lactic acid accumulation. 

Lactic acidosis. Patients in shock will often suffer from lactic acidosis due to a deficiency of O2. Why does a lack of O2 lead to lactic acid accumulation One treatment for shock is to administer dichloroacetate, which inhibits the kinase associated with the pyruvate dehydrogenase complex. What is the biochemical rationale for this treatment ... 

Metabolic acidosis with an increased SAG commonly results from increased endogenous organic acid production. In lactic acidosis, lactic acid accumulates as a by-product of anaerobic metabolism. Accumulation of the ketoacids /S-hydroxybutyric acid and acetoacetic acid defines the ketoacidosis of uncontrolled diabetes mellitus, alcohol intoxication, and starvation (see Table 51-5). In advanced renal failure, ac-cumulation of phosphate, sulfate, and organic anions is responsible for the increased SAG, which is usually less than 24 mEq/L." The severe metabolic acidosis seen in myoglobinuric acute renal failure caused by rhabdomyolysis may be caused by the metabolism of large amounts of sulfur-containing amino acids released from myoglobin. 

Lactate production is a normal part of metabolism. In the absence of disease, elevated lactate levels in the blood are associated with anaerobic glycolysis during exercise. In lactic acidosis, lactic acid accumulates in blood to levels that significantly affect the pH (lactate levels greater than 5 mM and a decrease of blood pH below 7.2). 

The lactic acid accumulated during the production of fermented milks and cheeses, besides the related pH drop, represents the key component for the antimicrobial effect of dairy LAB against many spoilage and/or pathogenic bacteria. On the other hand, in some dairy products, and mainly in vegetable-based fermented foods or in intermediate food products such as sourdough, acetic acid released by facultatively or obli-gately heterofermentative LAB can account for an additive preservative effect related to fermentation. 

Cyanide (CN ), carbon monoxide (CO) and azide (Ns") inhibit compiex IV. Hence, in cases of cyanide poisoning, despite the blood of the subjects being well oxygenated, they are incapable of aerobic metabolism. Consequently, their venous blood is red and similar in colour to their arterial blood. Also, lactic acid accumulates and stimulates the respiratory centre, causing hyperventilation. 

The acute attack is usually associated with the precipitation of urates. The solubility of the urates decreases with the pH. In the intact animal, lactic acid accumulation is the most likely responsible factor for acidification of the tissue. Lactic acid accumulation results from increased anaerobic glycolysis. 

Villee and his associates [116,117] also studied pyruvic acid dissimilation and usage as well as lactic acid accumulation in the presence and absence of insulin. Many of these experiments were performed in animals submitted to different hormonal treatments. Whereas in normal muscle insulin increases the amount of pyru-... 

Chronic pulmonary failure may be further complicated by metabolic disturbances tending to metabolic alkalosis or metabolic acidosis. The mechanism leading to alkalosis is not always clear, but among the factors that may influence it are the loss of hydrogen and Cl ions, because of vomiting or because of selective Cl and potassium depletion as a result of undernourishment, and prolonged treatment with diuretics. It is usually assumed that severe respiratory acidosis is always accompanied by metabolic acidosis. This reasoning is based on the fact that when the same CO2 tensions are achieved in the blood in vivo and in vitro,the plasma concentration of bicarbonate for identical pH s is lower in vivo than in vitro. In reality, this bicarbonate deficit seems to result because (I) the buffer curve of the blood CO2 has a lower slope in vivo than in vitro and (2) hyperventilation in vivo leads to lactic acid accumulation in he blood. 

Metabolic acidosis is, however, a rare complication of chronic pulmonary disease, except in cases of acute hypoxemia, which may lead to transient lactic acid accumulation in the blood. 

When GSH is administered immediately prior to glucose, large doses are necessary to increase either the glucose tolerance or the glucose-induced phosphate fall. Lactic-acid accumulations, if abnormally high in the absence of GSH, are decreased in the presence of GSH. Accumulations which are normal without GSH are unchanged with GSH. The reason for this difference is not known. 

---