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

In laboratory rodents, concentrations of reduced glutathione (GSH) are exceedingly high (up to 7 to 8 millimolar) in the glandular gastric tissue compared to concentrations in other portions of the gastrointestinal tract or to those of most other organs. Gastric GSH varies diurnally, with the highest levels occurring in the late afternoon or early evening. Starvation, treatment with diethyl maleate, or cold-restraint stress all caused marked decreases in stomach GSH, whereas treatment with cobaltous chloride caused an increase in the GSH concentrations. The physiological significance of the high gastric GSH is unknown, but because this endogenous compound may strongly modulate (decrease or increase) the macromolecular binding of certain chemicals capable of inducing stomach tumors, the possible role of glutathione in the pathogenesis of chemically induced gastric cancer should be considered.
 ...
PMID:High concentrations of glutathione in glandular stomach: possible implications for carcinogenesis. 57 89

Despite the growing use of fish in toxicological studies, little is known regarding glutathione (GSH) metabolism and turnover in these aquatic species. Therefore, we examined GSH metabolism in the liver and gills of channel catfish (Ictalurus punctatus), a commonly employed aquatic toxicological model. Treatment of channel catfish with L-buthionine-S,R-sulfoximine (BSO, 400 or 1000 mg/kg, i.p.), an inhibitor of GSH biosynthesis, did not deplete hepatic GSH in channel catfish. In addition, hepatic GSH concentrations did not fluctuate in catfish starved for 3 days, indicating relatively slow turnover of hepatic GSH. However, hepatic GSH concentrations were reduced significantly (P less than 0.05) after 7 days of starvation. Administration of the thiol alkylating agent diethyl maleate (DEM, 0.6 mL/kg, i.p.) resulted in depletion of 85% of hepatic GSH at 6 hr post-DEM, with complete GSH recovery observed at 24 hr post-DEM. Co-administration of BSO and DEM (1000 mg/kg, 0.6 mL/kg, respectively) substantially depleted gill GSH and eliminated detectable liver GSH. Following BSO/DEM, GSH recovery in hepatic mitochondria occurred more rapidly than did liver cytosolic GSH. gamma-Glutamylcysteine synthetase (GCS) activities were comparable in the 10,000 g supernatants of catfish liver and gills (204 +/- 21 and 268 +/- 20 nmol/min/mg protein, respectively) whereas gamma-glutamyltranspeptidase (GGT) activity was not detected in the 600 g post-nuclear fraction of either liver or gills. In conclusion, i.p. administration of DEM was an effective means for achieving short-term hepatic GSH depletion in channel catfish, whereas co-administration of BSO and DEM elicited prolonged and extensive hepatic GSH depletion in this species. Like rodents, channel catfish maintained physiologically distinct hepatic mitochondrial and cytosolic GSH pools, and also regulated hepatic GSH levels by in situ hepatic GSH biosynthesis. However, unlike rodents, there was no evidence for a labile hepatic cytosolic GSH pool in channel catfish. These similarities and differences need to be considered when designing toxicological studies involving the GSH pathway in channel catfish and possibly other fish species.
 ...
PMID:Effects of buthionine sulfoximine and diethyl maleate on glutathione turnover in the channel catfish. 135 Sep 5

The stimulation of DNA synthesis in lymphocyte populations was previously shown to depend strongly on the intracellular glutathione (GSH) level. Since T cell growth is known to depend on interleukin 2 (IL-2), the experiments in this report were designed to determine whether intracellular GSH depletion may inhibit IL-2 production or the IL-2 dependent DNA synthesis. Our experiments revealed that IL-2 production and DNA synthesis of mitogenically stimulated splenic T cells have indeed different requirements for GSH. The addition of relatively high concentrations of GSH (5 mM) to cultures of concanavalin A (Con A)-stimulated splenic T cells was found to augment strongly the DNA synthesis but inhibited the production of IL-2. Moderate intracellular GSH levels, however, are apparently not inhibitory for IL-2 production, since intracellular GSH depletion by cysteine starvation or by graded concentrations of DL-buthionine sulfoximine (BSO) had virtually no effect on IL-2-specific mRNA expression and the production of T cell growth factor (TCGF). The DNA synthesis activity, in contrast, was strongly suppressed after GSH depletion with either method. As in cultures of splenic T cells, GSH depletion had no substantial effect on the induction of IL-2 mRNA and TCGF production in several mitogenically stimulated T cell clones. Taken together, our experiments suggest that complex immune response may operate best at intermediate GSH levels that are not too high to inhibit IL-2 production but sufficient to support DNA synthesis.
 ...
PMID:Interleukin-2 mRNA expression, lymphokine production and DNA synthesis in glutathione-depleted T cells. 220 8

Stress and starvation increased liver metallothionein (MT) and decreased liver glutathione (GSH) levels. Serum cysteine plus cystine levels were increased by stress. The exogenous administration of GSH, while not modifying hepatic GSH content, increased liver MT levels in basal and starved rats but not in stressed rats. Liver and serum cysteine levels were increased by GSH administration, a process partially reverted by the irreversible inhibitor of gamma-glutamyl transpeptidase, alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid. Mouse and rat liver MT levels were also increased by buthionine sulfoximine, an inhibitor of GSH synthesis, indicating that GSH is not a necessary precursor of MT. In addition, the hepatic MT content was increased by the administration of cysteine in a dose-response manner. These results suggest that hepatic MT synthesis is elevated by increased cysteine pools, and that MT, GSH and cysteine levels are somehow inter-related. MT, besides GSH, may be contemplated as a putative intracellular reservoir of cysteine in the liver of adult rats.
 ...
PMID:On the metallothionein, glutathione and cysteine relationship in rat liver. 224 42

Starvation for 24 h causes a striking fall in glutathione content from 3.19 +/- 0.27 to 1.88 +/- 0.14 (X +/- SEM) mumol/g tissue and of GGT activity from 31.75 +/- 4.17 to 19.49 +/- 3.13 (X +/- SEM) nmol/min/mg protein in the homogenate from whole mucosa of the upper small intestinal segments. This was associated with a significant increase in GSH-Px activity and the content of lipid peroxides (measured by the thiobarbituric assay). On semi-synthetic iron-supplemented diet the activities of GSH-T and GGT were significantly decreased as compared with crude diet. On semisynthetic iron-depleted diet GSH-T and GGT activities were further depressed, but this was accompanied with an additional depression of GSH, glutathione reductase (GSSG-R), and glutathione peroxidase (GSH-Px) activities and lipid peroxide concentrations. Food deprivation significantly lowers the mucosal GSH-content and could lead to a destabilization of this system presumably by increased oxidative stress. As compared to normal "crude" diet, semisynthetic diets and oral iron depletion have been shown to cause a depression of the intestinal GSH system. As a consequence of these effects, the resistance of the small intestinal mucosa toward exogeneous dietary toxins might be reduced.
 ...
PMID:Glutathione and its related enzymes in the small intestinal mucosa of rats: effects of starvation and diet. 256 68

The relationship between carbon tetrachloride (CCl4)-induced hepatotoxicity and hepatic glutathione (GSH) content was investigated in fed and fasted rats. The elevation of serum glutamic-pyruvic transaminase (GTP) activity by CCl4 treatment was enhanced by fasting. Although the hepatic GSH content fo 12-hour-fasted rats was higher than that of fed rats determined at 6 p.m., the serum GPT activity of the former was higher than that of the latter. Starvation had no effect on the activities of hepatic glutathione peroxidase (GSH-Px) and glutathione reductase (GR). The results suggest that the potentiation of hepatic injury by CCl4 cannot be related to hepatic GSH content.
 ...
PMID:Relationship between hepatic glutathione content and carbon tetrachloride-induced hepatotoxicity in vivo. 271 15

Starved animals having low levels of erythropoietin in blood showed increased MDA, fluorescent pigments, and met-Hb values whereas the hemoglobin concentration decreased significantly on starvation. In vivo and in vitro studies with Ep reversed the effects of starvation and brought these values close to normal. The activities of the enzymes (SOD, catalase, GSH-PX, GR G6PD, and 6PGD) which protect the RBC membrane directly or indirectly from peroxidative threat, decreased on starvation and restored to normal levels after Ep treatment.
 ...
PMID:Effect of erythropoietin on membrane lipid peroxidation, superoxide dismutase, catalase, and glutathione peroxidase of rat RBC. 321 32

In this study we examined the response of the renal and hepatic glutathione (GSH) pool in rats to drastic GSH depletion treatments. For this purpose, we used a protein-free diet, starvation, and the injection of varying doses of diethyl maleate as depleting agents. We analysed GSH levels in both kidney and liver tissue homogenates after rats were fed a protein-free diet for 2 or 7 days or starved for 1, 2, or 3 days, as well as after diethyl maleate administration in a single maximal dose or in varying doses. The results indicated that the liver GSH pool was always more labile than the kidney GSH pool. Moreover, kidney GSH levels were almost unchanged after 7 days on a protein-free diet or after 2 days of starvation, while liver showed significant changes in GSH levels. When we analysed the repletion rate, kidney had higher kinetic parameters (k = 0.148 h-1) than liver (0.097 h-1). We conclude that efficient mechanisms of maintaining GSH levels exist in the kidney and these may serve to avoid GSH diminution and hence preserve renal function during states of GSH depletion.
 ...
PMID:Renal and hepatic glutathione pool modifications in response to depletion treatments. 356 25

Microplasmodia of Physarum polycephalum differentiate into spherules when the CaCl2 concentration of their nutrient medium is increased to 54mM (high-calcium). The salts starvation medium routinely used to induce differentiation contains 8mM CaCl2. This medium will not induce spherulation in the absence of a calcium salt; no other metal is essential. High-calcium also induces the spherulation of a strain of Physarum that had not been previously observed to spherulate. The striking increase in superoxide dismutase activity (SOD) and the decrease in glutathione concentration (GSH) that are characteristic of salts-induced spherulation do not occur in salts media containing high-calcium. In the absence of calcium, no significant change in SOD is observed and very little change in GSH occurs. The immediate effect of the oxidative stress associated with spherulation may be the release of calcium stores into the cytosol. The parameters modulating this stress are, in turn, sensitive to exogenous calcium concentrations.
 ...
PMID:Superoxide dismutase activity and glutathione concentration during the calcium-induced differentiation of Physarum polycephalum microplasmodia. 366 5

Alterations in endogenous free radical-scavenging defense mechanisms of rat tissues after body weight loss (induced by starvation for 72 h) associated with hypoinsulinemia were investigated. The activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and glutathione (GSSG) reductase as well as levels of reduced glutathione (GSH) were examined in several tissues and in erythrocytes. A complex pattern of changes was observed. CAT activities were increased in the heart and pancreas and decreased in the liver. SOD levels were decreased in the heart and increased in the kidney and pancreas. GSH-PX activities were increased only in the kidney, and levels of GSH were decreased only in the liver of starved animals. Erythrocytes from starved animals showed no alterations in the levels of major free radical-scavenging enzymes. However, GSSG reductase levels were lower in erythrocytes from starved animals, and this was associated with an increased susceptibility to H2O2-induced GSH depletion. Paradoxically, H2O2-induced malondialdehyde (MDA) production in erythrocytes from starved animals was lower than that in control erythrocytes. Our results suggest that, in studies of experimental diabetes, attention must be given to the influence of body weight loss per se on the biochemical alterations associated with this disease.
 ...
PMID:Starvation-related alterations in free radical tissue defense mechanisms in rats. 380 31


1 2 3 4 5 6 7 8 9 10 Next >>