Plasma aspartate aminotransferase

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. 

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. 

Mocarelli et al. (1986) conducted a 6-year study on clinical laboratory parameters of children exposed to 2,3,7,8-TCDD following the Seveso accident. ALT, aspartate aminotransferase (AST), GGT, alkaline phosphatase, cholesterol, and triglycerides in plasma and delta amino levulinic acid in urine were monitored yearly in exposed and control groups beginning in June, 1977, approximately 1 year after the incident. The children were 6-10 years old at the time of the accident 69, 528, and 874 resided in the A, B, and R zones, respectively. Chloracne was seen in 19, 0.7, and 4.6%, of the children in areas A, B, and R, respectively. Blood samples were drawn from 69, 83, and 221 children in areas A, B, and R,... 

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. 

Liver. In humans, chronic Cd exposure does not typically result in hepatotoxicity. In laboratory animals, the liver accumulates the largest concentrations of Cd after acute or chronic exposures. In chronically exposed rats, liver injury occurs prior to renal dysfunction. Chronic Cd effects in the liver include increased plasma activities of alanine and aspartate aminotransferases, structural irregularities in hepatocytes, and decreased microsomal mixed function oxidase and CYP450 activities. Acute exposures in rats result in hepatic necrosis, particularly in parenchymal cells. Additionally, rough endoplasmic reticulum deteriorates, while smooth endoplasmic reticulum proliferates. Mitochondria are also degraded. As is the case with chronic exposure, microsomal mixed function oxidases and CYP450s are inhibited. 

Water retention due to sodium chloride (salt) is a common manifestation that leads to weight gain. Edema is also found in patients with cardiac heart failure, renal insufficiency, liver cirrhosis, and hypo-proteinemia. When large doses are used to treat neoplastic diseases, compounds with 17-alkyl substitutions can cause cholestatic hepatitis at high doses, jaundice is the most common clinical feature with accumulation of bile in the bile capillaries. Jaundice usually develops after 2-5 months of therapy. It can be detected by increases in plasma aspartate aminotransferase and alkaline phosphatase. 

In a recent study, DR mice exhibited lower inflammatory damage induced by LPS. Balb/c mice were subjected to 40% DR and challenged with 25 pg of LPS. The DR mice had attenuated increases in the proinflammatory cytokines consistent with the lower liver damage characterized by lower plasma alanine aminotranferase (ALT), aspartate aminotransferase (AST) and histopathological analysis. The DR mice also had higher circulating corticosterone, a mediator of antiinflammatory action in DR,... 

With prolonged bed rest, fluid retention occurs and plasma protein and albumin concentrations may be decreased by an average of 0.5 and 0.3g/dL, respectively. The concentrations of protein-bound constituents are also reduced, although mobilization of calcium from bones with an increased free ionized fraction compensates for the reduced protein-bound calcium, so serum total calcium is less affected. Serum aspartate aminotransferase activity is usually slightly less in individuals confined to bed than in those undertaking normal physical activity. Initially and paradoxically, creatine kinase (CK) activity is increased as a result of its release from skeletal muscles, but ultimately, CK activity may be less than in active, healthy individuals. Serum potassium may be reduced by up to 0.5mmol/L because of reduction of skeletal muscle mass. 

Amphetamines increase the concentration of free fatty adds. Morphine increases the activity of amylase and lipase, alanine and aspartate aminotransferases, ALP and the serum bilirubin concentration. The concentrations of gastrin, TSH, and prolactin are also increased. In contrast the concentrations of insulin, norepinephrine, pancreatic polypeptide, and neurotensin are decreased. Heroin increases the plasma concentrations of cholesterol, thyroxine, and potassium. PCO2 is increased but PO2 is decreased. The plasma albumin concentration is also decreased. Cannabis increases the plasma concentrations of sodium, potassium, urea, chloride, and insulin but decreases those of creatinine, glucose, and urate. 

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. 

Zhou S, Gordon R, Bradbury M, Stump D, Kiang C, Berk P. Ethanol up-regulates fatty acid uptake and plasma membrane expression and export of mitochondrial aspartate aminotransferase in HepG2 cells. Hepatology 1998 27 1064-74. 

Increase in plasma potassium, phosphate, total acid phosphate, lactate dehydrogenase, hydroxy butyrate dehydrogenase, and aspartate aminotransferase... 

Because cytosolic enzymes such as aspartate aminotransferase, lipase, and amylase appear in the blood after liver or pancreatic damage, we hypothesized that FAEE synthase, which is both cystolic and membrane bound, is released into the blood of patients with liver or pancreatic disease. We demonstrated that patients with liver or pancreatic disease release FAEE synthase into their plasma in amounts proportional to the level of asparate aminotransferase, amylase, or lipase (Aleryani, 1996). The presence of FAEE synthase in plasma may permit nonoxidative ethanol metabolism in the circulation in such individuals, although this remains to be conclusively demonstrated. 

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... 

H56. Howie, A. F., Spencer, E., and Beckett, G. J., Measurement of plasma aspartate aminotransferase, alanine aminotransferase and glutathione S-transferase during and post-sedation by low-dose isoflurane or nidazolam. Clin. Chem. (Winston-Salem, N.C.) 38, 476-479... 

Other clinical pathology changes in cardiotoxicity are typically nonspecific and relate to the impairment in cardiac performance and activation of the neuroendocrine system. Other plasma measurements that may be altered by cardiotoxic compounds include electrolytes, proteins other than enzymes, lipids, and other enzymes with less tissue specificity, such as aspartate aminotransferase. 

The use of restraining procedures may affect biochemical values in small and, to a lesser extent, large laboratory animals. Increased plasma alanine and aspartate aminotransferase activities associated with restraint during collection have been... 

Reagents for enzyme measurement are known not to be optimal for the different species (e.g., the substrate concentrations required for the measurement of plasma aspartate aminotransferase [AST/GOT] in rats, dogs, and monkeys differed from the concentrations used for these human plasma enzymes (Dooley 1979). However, there remains a lack of data on the optimal conditions—in terms of buffer, substrate concentration, reaction times, etc.— required for the different species. There are no nationally or internationally agreed-upon recommendations for laboratory animal samples, so most analysts use reagents formulated for human enzymes. Temperature... 

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],... 

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