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)

Incorporation of D-3-hydroxy[3-14C]butyrate into lipid in vivo suggests that lactating mammary gland is a major site of ketone-body utilization. The incorporation decreases in short-term insulin deficiency (2h) and on starvation (24h), but increases again on refeeding (2h). The activity of cytosolic acetoacetyl-CoA synthetase parallels the changes in nutritional state, but is not affected by short-term insulin deficiency.
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PMID:Utlization of D-3-hydroxy[3-14C]butyrate for lipogenesis in vivo in lactating rat mammary gland. 3 71

Two transport systems for glucose were detected: a high affinity system with a Km of 27 muM, and a low affinity system with a Km of 3.3 mM. The high affinity system transported glucose, 2-deoxy-D-glucose (Km = 26 muM), 3-O-methylglucose (Km = 19 muM), D-glucosamine (Km = 652 muM), D-fructose (Km = 2.3 mM) and L-sorbose (Km = 2.2 mM). All sugars were accumulated against concentration gradients. The high affinity system was strongly or completely inhibited by N-ethylmaleimide, quercetin, 2,4-dinitrophenol and sodium azide. The system had a distinct pH optimum (7.4) and optimum temperature (45 degrees C). The low affinity system transported glucose, 2-deoxy-D-glucose (Km = 7.5 mM), and 3-O-methylglucose (Km = 1.5 mM). Accumulation again occurred against a concentration gradient. The low affinity system was inhibited by N-ethylmaleimide, quercetin and 2,4-dinitrophenol, but not by sodium azide. The rate of uptake by the low affinity system was constant over a wide temperature range (30--50 degrees C) and was not much affected by pH; but as the pH of the medium was altered from 4.5 to 8.9 a co-ordinated increase in affinity for 2-deoxy-D-glucose (from 52.1 mM to 0.3 mM) and decrease in maximum velocity (by a factor of five) occurred. Both uptake systems were present insporelings germinated in media containing sodium acetate as sole carbon source. Only the low affinity system could initially be demonstrated in glucose-grown tissue, although the high affinity system was restored by starvation inglucose-free medium. The half-ti me for restoration of high affinity activity was 3.5 min and the process was unaffected by cycloheximide. Addition of glucose to an acetate-grown culture inactivated the high affinity system with a half-life of 5--7.5 s. Addition of cycloheximide to an acetate-grown culture caused decay of the high affinity system with a half-life of 80 min. Regulation is thus thought to depend on modulation of protein activity rather than synthesis, and the kinetics of glucose, 2-deoxy-D-glucose and 3-O-methylglucose uptake would be consistent with there being a single carrier showing negative co-operativity. Analysis of transport defective mutants revealed defects in both transport systems although the mutants used were alleles of a single gene. It is concluded that this gene (the ftr cistron) is the structural gene for an allosteric molecule which serves both transport systems.
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PMID:Sugar transport in Coprinus cinereus. 3 8

A siderophore (microbial iron transport compound) was isolated from low iron cultures of Agrobacterium tumefaciens B6. The substance was characterized as a threonyl peptide of spermidine acylated with 3 residues of 2,3-dihydroxybenzoic acid, the carbonyl group of 1 residue of the latter participating in an oxazoline ring with the beta-hydroxyl of the threonine moiety. The compound, N-[3-(2,3-dihydroxybenzamido)propyl]-N-[4-(2,3-dihydroxybenzamido)butyl]-2-(2,3-dihydroxyphenyl)-trans-5-methyl-oxazoline-4-carboxamide, was given the trivial name agrobactin. Exposure to acid opened the oxazoline ring to afford agrobactin A. Ferric agrobactin A and agrobactin A itself, but not agrobactin or its ferric complex, had some capacity to feed iron to enterobactin-deficient strains of Escherichia coli and Salmonella typhimurium. Agrobactin was produced by A. tumefaciens in response to iron deficiency and was able to reverse the iron starvation in this organism precipitated by the presence of a ferric complexing agent not utilized by the cells.
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PMID:Agrobactin, a siderophore from Agrobacterium tumefaciens. 3 87

Factors contributing to modifications in the capability for enzyme adaptation as an expression of aging are reviewed. Specific examples of altered enzyme adaptations during aging include the responses of hepatic glucokinase activity to glucose and hepatic tyrosine aminotransferase activity to starvation in Sprague-Dawley rats. These impaired enzyme adaptations apparently are not the consequence of alterations in hepatic function during aging. Instead, they reflect disturbances in extrahepatic hormonal regulatory mechanisms. Specific examples include modifications in the control of circulating levels of insulin glucagon, corticosteroids, and thyroid hormones. Age-dependent changes in the regulation of circulating levels of insulin probably originate within the impaired ability of pancreatic islets of Langerhans to secrete the hormone in response to glucose. The rationale for exploiting this experimental approach as a means to understand biological aging is discussed.
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PMID:Loss of adaptive mechanisms during aging. 3 73

Inactivation of the nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase from Saccharomyces cerevisiae during carbon starvation occurs with a simultaneous loss of enzyme protein and enzyme activity.
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PMID:Regulation of Saccharomyces cerevisiae nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase by proteolysis during carbon starvation. 3 42

Experimental models of chronic and acute peptic ulcerations were produced in the albino rats by means of prolonged starvation and indomethacin administration. In the case of acute indomethacin-induced peptic ulceration, the effects of anticholinergic drugs on the ulcers produced were also studied. Starving the rats for a period of seven days produced gastric ulceration in all the rats used while indomethacin produced gastric ulceration within five hours in all the rats used. Severe ulceration of the degree found in human peptic ulcer disease was produced only by chronic starvation. Anticholinergic drugs ameliorated indomethacin-induced gastric ulceration, partly at least, by reducing intra-gastric acidity.
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PMID:Comparative studies on starvation - and indomethacin - induced ulcerations in albino rats. 3 60

The effects of streptozotocin-induced diabetes and of starvation on the lysyl oxidase activity of rat lung were investigated. Enzyme activity was elevated 2--3 fold in the lungs of streptozotocin-diabetic rats. In contrast, starvation of rats produced a rapid loss of lung lysyl oxidase activity, with levels approximating 25% of control values after 48--72 h of starvation. Enzyme activity was essentially fully restored to control values upon refeeding the 48-h starved animals for 3 h. These studies demonstrate the responsiveness of lysyl oxidase to these physiological states and suggest a component, enzymatic basis of change in lung function known to occur in the diabetic state.
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PMID:Changes in lung lysyl oxidase activity in streptozotocin-diabetes and in starvation. 3 20

The equilibrium distribution of 5,5-dimethyloxazoladine 2,4-dione (DMO) between intra- and extracellular volume was used to estimate intracellular pH (pHi) in Tetrahymena pyiformis. In control experiments, DMO was found to equilibrate rapidly in response to a pH gradient. Under normal growth conditions, pHi was constant over a finite range of external pH, being maintained near pH 7.1 over the external pH range 5.2 to 7.3. This same range of external pH was also optimal for growth. pHi was monitored during the cell cycle of a synchronous population of T. pyriformis GL. The cells were synchronized either by starvation/refeeding or heat shock. Under both conditions, there were two alkaline shifts of approximately 0.4 pH units per cell cycle. These shifts in pH retained a constant remporal relationship to S phase and were not affected by changes in the time, duration, or magnitude of cytokinesis.
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PMID:Intracellular pH changes during the cell cycle in Tetrahymena. 3 59

The intracellular levels of glutamine synthetase (GS) in Anacystis nidulans grown under different conditions were determined using a whole-cell assay. Nitrate-grown cells have 64% more GS than cells grown in ammonium sulfate. Nitrogen starvation does not affect GS levels appreciably. Incubation of nitrate-grown cells with ammonium sulfate does not change the ratio of gamma-glutamyl transferase activities stimulated by Mg2+ and Mn2+ ions. An in vitro test of adenylylation indicates that algae do not have an endogenous adenylyl transferase (ATase) and that algal GS is not adenylylatable by the Klebsiella aerogenes ATase. Some characteristics of the GS-membrane complex were determined by centrifugation of the complex under varying conditions of pH and ionic strength. In this way, it was shown that acid pH (4.5) stabilizes the complex and high ionic strength tends to solubilize the enzyme. A simple partial purification of GS (89-fold) was developed based on the sedimentation properties of GS.
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PMID:Distinctive properties of glutamine synthetase from the cyanobacterium Anacystis nidulans. 3 92

Lipogenic capacity of various dietary carbohydrates starch, glucose sucrose and lactose was tested during ad lib feeding and starvation followed by refeeding. Sucrose was found to have maximal effect on hepatic total lipid and the enzymes in the study followed by glucose and sago while lactose was found to be toxic. Starvation resulted depression in the activities of various enzymes. The enzyme activity inducing effect was again exhibited by sucrose diet during ad lib and restricted refeeding followed by starvation.
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PMID:Effect of different dietary carbohydrates on some hepatic dehydrogenases and total lipid during starvation and refeeding regimen. 3 90


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