Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(Na+,K+)ATPase activity of rat liver plasma membranes was evaluated in female rats feeding an ethanol containing diet for 46 days (total ethanol ingested, 59.7 g/100 g body wt). Determinations were performed at the end of ethanol treatment or at various times after stopping treatment. (Na+,K+)ATPase and 5'-nucleotidase activities exhibited a 8- and 1.4-fold decrease, respectively, at the end of ethanol ingestion. In contrast no modifications of Mg2+-ATPase activity were observed. There also occurred, in ethanol-treated rats, release of sorbitol dehydrogenase into the blood, fat accumulation in liver cells, and decrease in reduced glutathione (GSH) liver content. A decrease in (Na+,K+)ATPase activity was also found in plasma membranes isolated from hepatocyte suspensions after a 2-hr incubation with 50 mM ethanol or 1 mM acetaldehyde (ACA), in conditions that caused a great fall in hepatocyte GSH content but did not cause cell death. After the cessation of ethanol administration, there occurred a progressive recovery of (Na+,K+)ATPase activity, GSH and triacylglycerol content, and release of sorbitol dehydrogenase. These parameters reached control values 12 hr after ethanol withdrawal. S-Adenosyl-L-methionine (SAM), L-methionine, and N-acetylcysteine (NAC), given to rats during ethanol treatment, prevented the decrease in (Na+,K+)ATPase activity and GSH content. They also reduced steatosis and liver necrosis. The efficiency of these compounds decreased in this order: SAM, methionine, NAC. SAM accelerated the recovery of all parameters studied after ethanol withdrawal, and also protected (Na+,K+)ATPase activity and GSH content of isolated hepatocytes from the deleterious effect of ethanol. These SAM effects were prevented by 1-chloro-2,4-dinitro-benzene, a compound which depletes cell GSH. Treatment of isolated hepatocytes with [35S]SAM led to the synthesis of labeled GSH. The total amount and specific activity of labeled GSH underwent a significant increase, in the presence of 2 mM ethanol or 0.5 mM ACA, which indicates a marked stimulation of GSH synthesis by ethanol and ACA. These data indicate that ethanol intoxication may inhibit (Na+,K+)ATPase activity; an effect that does not seem to depend on cell necrosis. SAM, methionine, and NAC exert various degrees of protection toward ethanol-induced cell injury, which are related to the efficiency of these compounds in maintaining a high GSH pool.
 ...
PMID:Inhibition by ethanol of rat liver plasma membrane (Na+,K+)ATPase: protective effect of S-adenosyl-L-methionine, L-methionine, and N-acetylcysteine. 253 5

Changes in the properties of rat liver plasma membranes were examined in studies designed to differentiate between direct and metabolic effects of acute and chronic ethanol ingestion. One hour after a single dose of ethanol (3 g/kg body weight) there were increases in Na+,K+-ATPase (32%) and 5'-nucleotidase (36%), and hepatic concentrations of ethanol and acetaldehyde were approximately 23 mM and 50 microM, respectively. Na+,K+-ATPase and 5'-nucleotidase activities in liver plasma membranes from control rats were not significantly changed by in vitro addition of 30 microM acetaldehyde or 50 mM ethanol. Increases in Na+,K+-ATPase (approximately 20%) and 5'-nucleotidase (approximately 30%) were also observed in liver plasma membranes isolated from rats 16 hr after feeding ethanol or sucrose supplements for 17 days. The intake of calories from dietary protein and lipid was decreased by about 25% in both the ethanol and sucrose-fed animals. Na+,K+-ATPase activities in liver plasma membranes isolated from control rats were inhibited (approximately 20%) by 100 mM ethanol in vitro, whereas no inhibition was observed using membrane preparations from rats fed ethanol or sucrose supplements. Our results show that changes in liver plasma membrane enzyme activities associated with a single dose of ethanol are not a direct effect correlated with blood, hepatic or plasma membrane concentrations of ethanol or acetaldehyde. Chronic ingestion of ethanol or sucrose supplements had similar effects on liver plasma membrane enzyme characteristics and parallel changes in nutrient intake may be a more feasible explanation of these results than any analogous direct effects of the two compounds.
 ...
PMID:Effects of ethanol administration on rat liver plasma membrane-bound enzymes. 299 Apr 93

A spectrophotometric method is described for the determination of 5'-nucleotidase. In combination with the enzymes nucleoside phosphorylase and xanthine oxidase, inosine, formed by hydrolysis of 5'-IMP by 5'-nucleotidase, is cleaved phosphorolytically to hypoxanthine, which is oxidized to uric acid. In the presence of ethanol, the hydrogen peroxide formed is reduced by catalase and equivalent amounts of acetaldehyde are produced. The aldehyde is dehydrogenated (NADP-dependent) by aldehyde dehydrogenase and the production rate of NADPH is recorded at 334 nm. The inhibition of the unspecific cleavage of 5'-IMP by phosphatases is examined critically.
 ...
PMID:A new spectrophotometric method for the determination of 5'-nucleotidase. 625 57

The effect of ethanol on membrane enzymes (Na+, K+ and Mg2+ ATPases, 5'-nucleotidase, adenylate cyclase) alcohol dehydrogenase, aldehyde dehydrogenase and superoxide dismutase were studied in nerve cells (established cell lines, primary cultures of chick and rat brain) cultured in the presence of 100 mM ethanol, and in total rat brain, following various ethanol treatments of the rats (20% ethanol as the sole liquid source, intraperitoneal injection). The results show a difference between neuronal and glial cells. Most of the observed changes in enzymatic activities returned rapidly to control values when ethanol was withdrawn from the culture medium or from the diet. Alcohol dehydrogenase was more stimulated by ethanol than aldehyde dehydrogenase; therefore acetaldehyde may be accumulated. The inhibition of superoxide dismutase activity may allow an accumulation of cytotoxic O2- radicals in nervous tissue and may explain the polymorphism of lesions brought about by alcohol intoxication.
 ...
PMID:Ethanol and neuronal metabolism. 626 95