Influence of selenium on glutathione and some associated enzymes in rats with mammary tumor induced by 7,12-Dimethylbenz(a)anthracene
23 Mar 1996-Molecular and Cellular Biochemistry (Kluwer Academic Publishers)-Vol. 156, Iss: 2, pp 101-107
TL;DR: Observations clearly demonstrate the influence of dietary selenium supplementation in correcting abnormal changes in glutathione turnover and some associated enzymes in tumor induced rats.
Abstract: A recent finding in epidemiological and laboratory studies suggests that the ratio of selenium to glutathione is lower in breast cancer subjects than its control counterparts. Selenium, an antioxidant and anticarcinogen, can modify the status of glutathione and some associated enzymes by blocking peroxidation of lipids in membranes of cancer subjects. Studies were conducted using female albino rats of Wistar strain bearing mammary tumor induced by 7,12-dimethylbenz(a) anthracene to assess the biological role of selenium on some antioxidant enzymes associated with the maintenance of glutathione status. For induction of mammary tumor, 25 mg DMBA in a 1 ml emulsion of sunflower oil and physiological saline was injected subcutaneously to each rat. One group in each of control and tumor bearing rats, were fed 5 mg sodium selenite/kg diet from the day of tumor induction for 24 weeks. Increase in the reduced glutathione concentration was preceded by significant increase in the oxidized glutathione as well as in the activities of γ-glutamylcysteine synthetase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, and glucose-6-phosphate dehydrogenase by selenium administration in rats bearing tumor. However, selenium administration to rats bearing tumor decreased the activity of γ-glutamyl transpeptidase. These observations clearly demonstrate the influence of dietary selenium supplementation in correcting abnormal changes in glutathione turnover and some associated enzymes in tumor induced rats.
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TL;DR: Selenium supplementation to radiation treated oral cancer patients render improvement in the antioxidant status against oxidative stress, which represents the antioxidant property of selenium through the improvement of antioxidant defense system.
43 citations
TL;DR: Signal transduction studies suggests that selenium induces several changes in the MAPK signalling pathways but functional intervention/inhibitor studies indicate that activation of the JNK pathway seems to be most important.
Abstract: Accumulated evidence from prospective studies, intervention trials and studies on animal models of cancer have suggested a strong inverse correlation between selenium intake and cancer incidence. Several putative mechanisms have been suggested to mediate the chemopreventive activities of selenium: of these, the inhibition of cellular proliferation and the induction of apoptosis are particularly attractive. The mitogen activated protein kinase (MAPK) pathways are known to be important regulators of cell death and our recent work has focused on the involvement of these pathways in selenium-induced apoptosis in primary cultures of oral cancers and corresponding normal mucosa derived from biopsy material. Using this system, the oral carcinoma cells were found to have enhanced sensitivity to apoptosis when treated with certain selenium compounds compared to normal oral mucosa. Induction of Fas ligand was associated with selenium-induced apoptosis. Signal transduction studies suggests that selenium induces several changes in the MAPK signalling pathways but functional intervention/inhibitor studies indicate that activation of the JNK pathway seems to be most important.
41 citations
TL;DR: Oral administration of ethanolic extract of J. grandiflorum flowers (JgEt) at a dose of 300 mg/kg body weight for 14 weeks to DMBA‐injected animals completely prevented the formation of tumors in the pre‐initiation period and exerted significant anti‐lipid peroxidative effect.
Abstract: The aim of this study was to investigate the chemopreventive efficacy and anti-lipid peroxidative potential of Jasminum grandiflorum Linn. on 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary carcinogenesis. Mammary tumors were developed by a single subcutaneous injection of 25 mg DMBA in 1 mL emulsion of sunflower oil and physiological saline. The tumor incidence and tumor volume that formed in the breast were determined. Oral administration of ethanolic extract of J. grandiflorum flowers (JgEt) at a dose of 300 mg/kg body weight for 14 weeks to DMBA-injected animals completely prevented the formation of tumors in the pre-initiation period. JgEt also exerted significant anti-lipid peroxidative effect and improved the antioxidant defense system in DMBA-treated rats. The results of this study clearly indicate that JgEt has potent chemopreventive efficacy in experimental mammary carcinogenesis and further studies are warranted to isolate and characterize the bioactive principle from JgEt.
39 citations
TL;DR: Results indicate that p-XSC is a potent inducer of GSH and related thiol antioxidants in the lung leading to decreased levels of oxidative stress and suggest that p -XSC inhibits tumor formation, in part, by protecting against oxidative damage.
37 citations
TL;DR: Results suggested that AITC at a dose of 20 mg/kg bw significantly exert chemopreventive potential against DMBA-induced mammary carcinogenesis in female Sprague-Dawley rats.
36 citations
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Journal Article•
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
289,852 citations
"Influence of selenium on glutathion..." refers methods in this paper
...Total protein was determined by the method of Lowry et al. [ 19 ] GSH and oxidized glutathione (GSSG) concentrations were determined according to the method of Tietze [20] as modified by Griffith for GSSG [21 ]....
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TL;DR: When hemolyzates from erythrocytes of selenium-deficient rats were incubated in vitro in the presence of ascorbate or H2O2, added glutathione failed to protect the hemoglobin from oxidative damage.
Abstract: When hemolyzates from erythrocytes of selenium-deficient rats were incubated in vitro in the presence of ascorbate or H(2)O(2), added glutathione failed to protect the hemoglobin from oxidative damage. This occurred because the erythrocytes were practically devoid of glutathione-peroxidase activity. Extensively purified preparations of glutathione peroxidase contained a large part of the (75)Se of erythrocytes labeled in vivo. Many of the nutritional effects of selenium can be explained by its role in glutathione peroxidase.
6,893 citations
"Influence of selenium on glutathion..." refers background in this paper
...established the central role of selenium in GSH metabolism and its function as the internal moiety of the selenoenzyme, glutathione peroxidase (GPx) [10]....
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...[10], Massey and Williams [22], and HaNg and Jacoby [23], respectively....
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TL;DR: The use of the foregoing analytical method in the determination of total and oxidized glutathione contents of rat blood, kidney, and liver gave values in good agreement with those obtained by previous investigators.
5,900 citations
"Influence of selenium on glutathion..." refers methods in this paper
...[19] GSH and oxidized glutathione (GSSG) concentrations were determined according to the method of Tietze [20] as modified by Griffith for GSSG [21 ]....
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5,223 citations