Plasma alanine aminotransferase

Use of the plasma enzyme alanine aminotransferase (ALT) in monitoring the progress of infectious hepatitis. 

Hepatic Effects. Liver function tests (serum bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase) completed in 11 hexachloroethane workers were within the normal range (Selden et al. 1994). Plasma hexachloroethane levels in these workers, who wore protective equipment, were 7.3 + 6.04 pg/L at the time of the tests (Selden et al. 1993). Mild skin and mucous membrane irritation were reported in the exposed group, suggesting that exposure may have been through either the inhalation or dermal routes of exposure. 

Dayal et al. (1989) treated BALB/c mice intraperitoneally with a single dose of 9 mmol/kg bw 2-nitropropane. In male mice, plasma activities of the hepatic enzymes sorbitol dehydrogenase, alanine aminotransferase and aspartate aminotransferase were significantly elevated, while doses of 6.7 mmol/kg bw were ineffective. In female mice, a dose of 6.7 mmol/kg bw was sufficient to cause hepatotoxicity. Histopathological evaluation revealed hepatic damage, particularly in the periportal region. 

Some enzymes show relatively high activity in only one or a few tissues. The presence of increased levels of these enzymes in plasma thus reflects damage to the corresponding tissue. For example, the enzyme alanine aminotransferase ALT, see p. 248) is abundant in the liver. The appearance of elevated levels of ALTin plasma signals possible damage to hepatic tissue. Increases in plasma levels of enzymes with a wide tissue distribution provide a less specific indication of the site of cellular injury. This lack of tissue specificity limits the diagnostic value of many plasma enzymes. 

Pattern of serum alanine aminotransferase (ALT) and bilirubin in the plasma, following poisoning with the toxic mushroom Amanita phalloides. 

Reasons for the presence of enzymes in the plasma Enzymes can normally be found in the plasma either because they were specifically secreted to fulfill a function in the blood, or because they were released by dead or damaged cells. Many diseases that cause tissue damage result in an increased release of intracellular enzymes into the plasma. The activities of many of these enzymes (for example, creatine kinase, lactate dehydrogenase, and alanine aminotransferase) are routinely determined for diagnostic purposes in diseases of the heart, liver, skeletal muscle, and other tissues. 

Amino groups are tunneled to glutamate from all amino acids except lysine and threonine. The enzymes are aminotransferases, and they are reversible. The two most important of these enzymes are alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Aminotransferases require pyridoxal phosphate as a coenzyme. The presence of elevated levels of aminotransferases in the plasma can be used to diagnose liver disease. 

Both aspartate aminotransferase and alanine aminotransferase are released into the blood after damage to tissues or after cell death. Consequently, they are used as diagnostic tools when heart or liver damage has occurred, such as after a heart attack or in hepatitis, respectively. Other enzymes are also released into the blood at such times. For example, damage to heart muscle is further characterized by the presence of isoenzymes of creatine kinase or lactate dehydrogenase in the plasma. 

BCAA catabolism, 209 chemical structure, 18 plasma concentrahon, 465 waste nitrogen and, 209-210 Alanine aminotransferase, 426 Alanine cycle, amino transferases and, 427-428... 

ANTIFUNGAL, ANTIMICROBIAL and ANTIINFLAMMATORY activity, and to be a powerful cytotoxic agent (functioning by DNA intercalation and uncoupling of oxidative phosphorylation). It is an ENZYME INHIBITOR (alanine aminotransferase and human plasma diamine oxidase). It shows antiplaque activity, and has been used in toothpastes and oral rinses. Causes temporary change in intraocular pressure. Sanomigran pizotifen. 

Within a few minutes of an infant s birth, fluid passes from the blood vessels into the extravascular spaces. This fluid is similar to plasma except that the fluid lost from the intravascular space contains no protein. Consequently the plasma protein concentration increases. The serum activities of several eu2ymes, including CK, GGT, and AST, are high at birth, but the increase of alanine aminotransferase (ALT) activity is less than that of other enzymes. 

There are five enzymes that are commonly used in diagnosis of liver disease Aspartate aminotransferase (AST EC 2.6.1.1), alanine aminotransferase (ALT EC 2.6.1.2), alkaline phosphatase (ALP 3.1.3.1), and y-glutamyl transferase (GGT EC 2.3.2.2), are commonly used to detect liver injury, and lactate dehydrogenase (LD EC 1.1.1.27) is occasionaEy used. ALT and GGT are present in several tissues, but plasma activities primarily reflect liver injury. AST is found in liver, muscle (cardiac and skeletal), and to a liipited extent iti fed cells. LD has wide tissue distribution, and is thus relatively nonspecific. ALP is found in a number of tissues, but in normal individuals primarEy reflects bone and liver sources. Thus based on tissue distribution, ALT and GGT would seem to be the most specific markers for liver injury. 

The standard battery of biochemical tests used to assess liver function usually includes the measurement of the activity in plasma of one of the aminotransferases [either aspartate aminotransferase (AST) or alanine aminotransferase (ALT)]. Such measurements are performed to assess the integrity of the hepatocyte membrane. The measurement of AST provides poor organ specificity due to the ubiquitous nature of the enzyme and both ALT and AST are relatively poor at detecting damage that is occurring to the centrilobular hepatocytes. The inadequacy of the aminotransferases at detecting centrilobular liver damage may be... 

Beckett, G. J., Foster, G. R., Hussey, A. J., Oliveira, D. B.G., Donovan, J. W., Prescott, L. F., and Proudfoot, A. T., Plasma glutathione S-transferase and F protein are more sensitive than alanine aminotransferase as markers of paracetamol (acetaminophen)-induced liver damage. Clin. Chem. (Winston-Salem, N.C.) 35, 2186-2189 (1989). 

Evans, G. O., and L. C. Whitehom. 1995. Effects of pyridoxal 5 -phosphate on plasma alanine aminotransferase determinations in toxicological studies. Toxicology Letters 80 34—37. 

The liver transaminases measured in the blood are aspartate aminotransferase (AST), which was formerly called serum glutamate-oxaloacetate transaminase (SCOT), and alanine aminotransferase (ALT), which was formerly called serum glutamate pyruvate transaminase (SGPT). Elevation of liver enzymes reflects damage of the liver plasma membrane. 

There was no evidence of apoptosis in the hearts of mice injected with toxic doses of yessotoxin, and no signs of myo- or hepato-toxicity, as indicated by normal plasma activities of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatine kinase [67],... 

A study, undertaken to confirm the involvement of the cytochrome P450 isoenzyme CYT2D6 in the metabolism of trazodone, found that when 11 depressed patients were given trazodone 150 to 300 mg at bedtime for 18 weeks, and then with thioridazine 20 mg twice daily for one week, the plasma levels of the trazodone and its active metabolite, /w-chlorophenyl-piperazine, rose by 36% and 54%, respectively. No adverse reactions were described. In contrast, a case of fatal hepatic necrosis with cholestasis has been attributed to the concurrent use of trazodone and phenothiazines. A 72-year-old woman taking trifluoperazine, trazodone and lithium carbonate developed an elevated alanine aminotransferase level. Trifluoperazine was replaced with thioridazine, but 9 weeks later she became jaundiced and developed hepatic encephalopathy, and died 6 weeks after the onset of jaundice. The authors consider that the combination of the phenothiazines and trazodone were the cause of her hepatic necrosis both phenothiazines and trazodone have been reported to individually cause hepatic adverse effects. ... 

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