Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P47989 (xanthine oxidase)
 8,633 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although it has long been known that energy restriction (ER) inhibits tumors and retards aging in rats and mice, its mode of action remains unknown. In rodents, ER alters the rate of age-related changes in physiological indices. Thus, it affects a broad array of age-sensitive parameters. However, present evidence does not indicate which parameters are primary contributors to the deceleration of aging. Compared to fasting or short-term underfeeding, little is known about the metabolic effects of long-term, life-prolonging ER. We thus investigated the effects of ER on hepatic enzyme activities, including drug-metabolizing enzymes and antioxidant enzymes such as superoxide dismutase and catalase. The catalase activity was found to be higher in ER mice than in control mice both at 12 and 24 months of age. In accord with the high catalase activity, lipid peroxidation in liver was much less in ER mice than in age matched control mice. beta-Naphthoflavone, known to induce P-450 related enzymes and xanthine oxidase, was given (ip) to increase lipid peroxidation. The ER was found to inhibit lipid peroxidation after beta-naphthoflavone treatment. It was, therefore, concluded that long-term life-prolonging ER increases antioxidant defence, supporting indirectly the free radical theory of aging. It is well known that ER delays puberty in rodents and has a profound influence on serum hormone levels, including those of prolactin (PRL) and thyroid hormones. However, it remains unknown how these effects are produced by ER. We therefore investigated the effects of ER on the islets of Langerhans in the pancreas and on the pituitary-ovarian axis. In the islets of Langerhans, ER was found to increase the density of alpha-cells significantly both in 11- and 67-week-old mice. In the pituitary gland in ER mice, the cellular density of PRL-producing cells diminished significantly while that of growth-hormone-producing cells did not. One of the modes of action of ER on the endocrine system is thus concluded to be mediated by changing cellular population. Since ER decreased PRL-producing cells and PRL plays a key role in mammary tumorigenesis, we investigated whether ER decreased the gene expression of mouse mammary tumor virus (MMTV) in SHN/C3H mice. The SHN strain, which was found to have a new MMTV provirus locus, mtv-4, was used in the study.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[On the mechanisms of retardation of aging and inhibition of mammary tumorigenesis by energy restriction in SHN/C3H F1 female mice]. 174 5

Xanthine oxidase/dehydrogenase (XO/XDH) increases at mid gestation in mammary gland but not in liver of the mouse and remains elevated until the pups are weaned at 20 d post partum. The increase in enzyme activity is due neither to alteration in activators or inhibitors nor to a production of a variant enzyme with altered catalytic properties. The increase is preceded in vivo by a surge of prolactin-like activity (placental lactogen) in plasma, and prolactin is required for induction of XO/XDH in explant culture in vitro. Induction of XO/XDH in vivo and in vitro precedes the full histological differentiation of the gland. In addition, induction of XO/XDH in vitro occurs more rapidly and at lower concentrations of prolactin than does histological differentiation. Thus although XO/XDH is present in milk, increased XO/XDH activity is an early event in mammogenesis in vivo and in vitro rather than a terminal component of differentiation.
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PMID:Xanthine oxidase/dehydrogenase in mammary gland of mouse: relationship to mammogenesis and lactogenesis in vivo and in vitro. 176 90

The use of xanthine oxidase (XO) as a label in immunoanalysis has not been previously reported. This can be explained by the difficulties encountered in XO assays (poor sensitivity and versatility) and the competitive inhibition of the enzyme by allopurinol, a widely used hypouricemic agent. We demonstrate here that both difficulties can be circumvented. (i) The XO-dependent luminescent signal related to the oxidation of luminol is dramatically enhanced in the presence of iron-EDTA complex and sodium perborate in alkaline buffer. The mechanism of this enhancement is consistent with an O2-driven Fenton reaction, leading to the production of highly reactive OH radical. (ii) Residual inhibition of solid-phase bound XO by serum allopurinol and its metabolites is spontaneously reversible and can be prevented by the presence of folic acid or azahypoxanthine in the incubation buffer. With these two problems solved, XO can be classified as a choice label in immunoanalysis with the following properties: (i) high detection sensitivity (3 amol label), (ii) long-term luminescent signal (several days), (iii) versatile preparation and stability of conjugates, and (iv) long-term stability of the luminescence reagent. As an example of application, some data concerning total IgE and direct 17 beta-estradiol assays are described. Several other luminescent immunoassays of large and small molecules have been developed using XO conjugates as tracer (free and total T4, ultrasensitive thyroid stimulating hormone, CA 19.9, prolactin, hCG, specific IgE, anti-toxoplasma, and anti-chlamydia IgG), thus proving that XO can be classified as a universal label.
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PMID:Application of a long-term enhanced xanthine oxidase-induced luminescence in solid-phase immunoassays. 211 11

A cDNA encoding mouse butyrophilin was obtained by reverse transcriptase-coupled polymerase chain reaction (RT-PCR) using poly (A)+ RNA from lactating mouse mammary gland as a template and screening a cDNA library with the RT-PCR-amplified fragment as a probe. DNA sequencing and computer analysis revealed that it has a rather long 3'-untranslated sequence and that the carboxy-terminal cytoplasmic domain was well conserved between mouse and bovine butyrophilins. To elucidate the biological function of butyrophilin, the cytoplasmic region expressed as fusion protein with glutathione S-transferase (GST) was purified and incubated with the cell lysate of mouse mammary epithelial cell lines, COMMA-ID and HC11. A 150-kDa protein was shown to specifically associate with the cytoplasmic domain and the protein increased in amount when the cells were treated with basal medium supplemented with lactogenic hormones such as prolactin, insulin and glucocorticoid. N-terminal amino acid sequencing indicated that the protein is xanthine dehydrogenase/oxidase which has been cloned from mouse liver. Further, the cytoplasmic domain also bound xanthine dehydrogenase/oxidase from bovine milk fat globule membrane. These results suggest that butyrophilin might be physiologically associated with xanthine dehydrogenase/oxidase and might function in a complex form in milk fat secretion.
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PMID:Carboxy-terminal cytoplasmic domain of mouse butyrophilin specifically associates with a 150-kDa protein of mammary epithelial cells and milk fat globule membrane. 854 2