Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Levels of the mRNA encoding the catalytic subunit of protein phosphatase type-1 (PP-1cat) were reduced in skeletal muscle but not liver in response to short-term (2h) chow refeeding after prolonged (40h) starvation in the rat. This reduction did not appear to be mediated by insulin per se since streptozotocin-induced diabetes was associated with a reduction in PP-1cat levels in skeletal muscle. It is suggested that glucose levels may be one factor that modulates skeletal muscle PP-1cat mRNA levels. Despite the changes in PP-1cat mRNA levels in skeletal muscle, total protein phosphatase-1 catalytic activity was not altered by either chow refeeding or streptozotocin-diabetes. By contrast, although total hepatic PP-1cat mRNA levels were not altered in response to chow refeeding, there was a marked reduction in glycogen phosphorylase phosphatase activity in the cytosol but not in the glycogen/microsomal fraction.
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PMID:Protein phosphatase type-1 mRNA levels in response to starvation-refeeding and streptozotocin-diabetes. 754 40

The regulation of hepatic mitochondrial carnitine palmitoyltransferase-I (CPT-I) was studied in rats during starvation and insulin-dependent diabetes and in rat H4IIE cells. The Vmax. for CPT-I in hepatic mitochondrial outer membranes isolated from starved and diabetic rats increased 2- and 3-fold respectively over fed control values with no change in Km values for substrates. Regulation of malonyl-CoA sensitivity of CPT-I in isolated mitochondrial outer membranes was indicated by an 8-fold increase in Ki during starvation and by a 50-fold increase in Ki in the diabetic state. Peroxisomal and microsomal CPT also had decreased sensitivity to inhibition by malonyl-CoA during starvation. CPT-I mRNA abundance was 7.5 times greater in livers of 48-h-starved rats and 14.6 times greater in livers of insulin-dependent diabetic rats compared with livers of fed rats. In H4IIE cells, insulin increased CPT-I sensitivity to inhibition by malonyl-CoA in 4 h, and sensitivity continued to increase up to 24 h after insulin addition. CPT-I mRNA levels in H4IIE cells were decreased by insulin after 4 h and continued to decrease so that at 24 h there was a 10-fold difference. The half-life of CPT-I mRNA was 4 h in the presence of actinomycin D or with actinomycin D plus insulin. These results suggest that insulin regulates CPT-I by inhibiting transcription of the CPT-I gene.
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PMID:Insulin regulates enzyme activity, malonyl-CoA sensitivity and mRNA abundance of hepatic carnitine palmitoyltransferase-I. 757 18

Acetaminophen is the most commonly reported drug overdose in the United States. Acute renal failure occurs in less than 2% of all acetaminophen poisonings and 10% of severely poisoned patients. At the therapeutic dosages, acetaminophen can be toxic to the kidneys in patients who are glutathione depleted (chronic alcohol ingestion, starvation, or fasting) or who take drugs that stimulate the P-450 microsomal oxidase enzymes (anticonvulsants). Acute renal failure due to acetaminophen manifests as acute tubular necrosis (ATN). ATN can occur alone or in combination with hepatic necrosis. The azotemia of acetaminophen toxicity is typically reversible, although it may worsen over 7 to 10 days before the recovery of renal function occurs. In severe overdoses, renal failure coincides with hepatic encephalopathy and dialysis may be required. Recognition of acetaminophen nephropathy requires the following: (1) a thorough drug history, including over-the-counter medications such as Tylenol or Nyquil; (2) knowledge of the risk factors that lessen its margin of safety at therapeutic ingestions, i.e., alcoholism; and (3) consideration of acetaminophen in the differential diagnosis of patients who present with combined hepatic dysfunction and ATN.
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PMID:Acute renal failure due to acetaminophen ingestion: a case report and review of the literature. 757 69

1. An increase in the ionic strength of the assay medium markedly increased the basal activity of the malonyl-CoA-sensitive carnitine medium/long chain acyltransferases in peroxisomes and microsomes and decreased the malonyl-CoA inhibition. 2. ATP-Mg largely reversed the salt mediated stimulation of both the peroxisomal and the microsomal activities. 3. The octylglucoside solubilization of the peroxisomes and microsomes caused only marginal losses of their catalytic activity but the malonyl-CoA inhibition was nearly fully abolished. 4. Starvation increased the above activity of peroxisomes and microsomes and decreased their sensitivity to malonyl-CoA inhibition. Tritiated etomoxir labeled a approximately 47 kDa peptide in these organelles, the intensity of which was decreased on starvation. Collectively these findings strengthen the notion that the malonyl-CoA sensitive carnitine acyltransferases in mitochondria, microsomes, and peroxisomes are distinct proteins.
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PMID:Some properties of the malonyl-CoA sensitive carnitine long/medium chain acyltransferase activities of peroxisomes and microsomes of rat liver. 783 27

Ethanol-inducible cytochrome P450 (CYP) 2E1 (CYP2E1) is responsible for the metabolism of many xenobiotics which exert toxic effects in humans. Specific inhibitors might constitute valuable tools in the elucidation of the pharmacological and toxicological roles of this isozyme in vivo. In the present investigation we have evaluated the effects of a drug used for treatment of ethanol withdrawal states, chloromethiazole (CMZ), on CYP2E1 expression in rat liver. A 4-fold induction of CYP2E1 was observed after 3 days of starvation, accompanied by a similar increase in the level of the corresponding mRNA. CMZ specifically inhibited the elevation of CYP2E1 mRNA and protein, but did not prevent CYP2B1 and CYP3A1 or CYP1A1 induction caused by treatment with phenobarbital or beta-naphthoflavone, respectively. From nuclear run-off experiments it was apparent that the rate of the CYP2E1 gene transcription was inhibited greatly by CMZ treatment. Rats treated with ethanol in a total enteral nutrition model had higher CYP2E1-dependent hepatic microsomal activities of p-nitrophenol hydroxylase and carbon tetrachloride-induced lipid peroxidation than controls, and simultaneous CMZ treatment abolished the ethanol-dependent induction. In vitro experiments with rat liver microsomes showed that CMZ did not act as an inhibitor of CYP2E1-dependent catalytic activities or as an inhibitor of microsomal NADPH and CYP2E1-dependent lipid peroxidation. In conclusion, we suggest that CMZ might constitute an efficient and specific inhibitor of CYP2E1 expression suitable for in vivo experiments.
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PMID:Chlormethiazole as an efficient inhibitor of cytochrome P450 2E1 expression in rat liver. 801 72

The hepatic microsomal glucose-6-phosphatase enzyme was studied in liver samples from 76 premature infants including 15 victims of sudden infant death syndrome. The data obtained were compared with glucose-6-phosphatase activity in liver samples from 95 term infants. In the majority of preterm infants up to 350 days of age the activity of the glucose-6-phosphatase enzyme was at or below the extreme low limit of the normal range in term infants. The premature infants with the lowest hepatic microsomal glucose-6-phosphatase activities are likely to be at risk of hypoglycaemic episodes during periods of relative starvation or stress.
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PMID:Abnormal expression of glucose-6-phosphatase in preterm infants. 838 19

Microsomal lauric acid 12-hydroxy lauric acid (omega)-hydroxylation and fatty acid peroxisomal beta-oxidation were studied in kidney tissue from starved rats. Starvation increased the microsomal omega-hydroxylation and peroxisomal beta-oxidation of fatty acids with a high correlation between both processes. Earlier, we reported similar results in liver. Our results support the hypothesis that the role of microsomal fatty acids omega-hydroxylation is the generation of substrate for peroxisomal beta-oxidation, with the final purpose of contributing to a catabolic or gluconeogenic pathway from fatty acids.
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PMID:Starvation effect on rat kidney peroxisomal and microsomal fatty acid oxidation. A comparative study between liver and kidney. 848 69

2,4,5,2',4',5'-hexachlorobiphenyl (HCB) induces hepatic microsomal cytochromes P450 with a similar selectivity for responsive genes to phenobarbital (PB). CYP2Bl, CYP2B2, CYP2C6, CYP3Al, and CYP2Al each showed large strain differences in induction by HCB Fisher F344 >> Wistar Furth (WF) that were much more evident in female rats, paralleling previous observations with PB. These five P450s and epoxide hydrolase were, however, induced more effectively by HCB than by PB and strain differences were even larger. With HCB, strain differences in male rats were much more apparent than with PB. This change was not due to the greater HCB induction since a 2-fold lower induction was maintained even with a 10-fold lower dose of HCB. The sex and strain differences were seen both by immunoblot analysis and by form-selective enzyme activity assays. induction of CYP2B1, CYP2B2, and CYP3A1 by HCB was decreased 3-fold when starvation during the final 24 hr was replaced by continuous feeding. This effect was similar in each strain and therefore independent of the regulatory processes associated with the differential suppression of induction in WF rats. This modulation of induction by feeding was also seen with PB which caused only a 30% lowering of induction in continuously fed F344 rats. A 52-kDa microsomal protein (p52) was prominently induced by both HCB and PB after starvation, while minor induction of a 50-kDa microsomal protein (p50) also occurred after the same treatment. Furthermore, a 100-kDa microsomal protein (p100) was induced by HCB but not by PB and only in rats that were continuously fed. These results suggest that the induction of multiple forms of P450 following HCB treatment functions through the same PB-stimulated pathway that shows a strain-dependent endocrine (GH/T3/testosterone)-sensitive suppression mechanism. The induction of p5O, p52, and plOO by HCB suggests the presence of at least two additional hepatic response mechanisms for HCB.
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PMID:The regulation by gender, strain, dose, and feeding status of the induction of multiple forms of cytochrome P450 isozymes in rat hepatic microsomes by 2,4,5,2',4',5'-hexachlorobiphenyl. 868 6

Upon fractionation of a post mitochondrial supernatant from rat liver, phosphorylase kinase activity was largely recovered in the cytosol and the smooth endoplasmic reticulum (SER) fraction. The presence of phosphorylase kinase in SER vesicles was not due to an interaction of the enzyme with glycogen particles, since previous elimination of SER glycogen either by 48 h animal starvation or by treatment of the membrane fraction with alpha-amylase did not significantly alter phosphorylase kinase activity content. Washing of the initial pellet of SER fraction (crude SER) by dilution and recentrifugation, released in the supernatant an amount of phosphorylase kinase activity, which is dependent on: i) the degree of dilution, ii) the number of washes, iii) the ionic strength of the washing solution and iii) the presence or absence of Ca2+. Crude SER-associated phosphorylase kinase was marginally affected by increased concentrations of antibody against rabbit skeletal muscle holoenzyme which nevertheless drastically inhibited cytosolic enzyme activity, while it showed a higher resistance to partial proteolysis and a different Western blotting profile with anti-phosphorylase kinase when compared with the soluble kinase. A small but significant fraction of SER phosphorylase kinase was strongly associated with the microsomal fraction being partly extractable only in presence of detergents. This membrane-bound enzyme form exhibited an alkaline pH optimum, in contrast to the neutral pH optima of both soluble and weakly associated phosphorylase kinase.
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PMID:The association of phosphorylase kinase with membranes of rat liver smooth endoplasmic reticulum. 871 29

There is evidence to suggest that the mechanism of antioxidant effect of prostaglandin E1 (PGE1) is due to decrease of radical species generation by cytochrome P-450 in rat liver microsomes. Chronic alcohol intoxication increased NADPH oxidation, cytochrome P-450 content and NADPH-stimulated chemoluminiscence of microsomes. Ethanol also raised superoxide dismutase (SOD) activity in microsomes. PGE1 decreased cytochrome P-450 content, normalized NADPH oxidation, NADPH-induced chemoluminiscence and SOD activity in the liver of alcohol-treated rats. PGE developed the similar effect after microsomal induction by both acetone combined with starvation and phenobarbital normalizing all the above parameters. Therefore, PGE1 affects on both, ethanol-inducible IIE1 and phenobarbital-inducible IIB1 isoforms.
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PMID:Cytochrome P-450 and free radical generation in rat liver microsomes under the influence of prostaglandin E1. 887 71


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