Ornithine Decarboxylase Antizyme in Mammalian Tissues

Brosnan, Margaret E.; Hu, Yu-Wan

doi:10.1007/978-1-4684-5637-0_4

Cited by 5 publications

(6 citation statements)

References 24 publications

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“…of tissue (Tabor & Tabor, 1976Pegg & McCann, 1982). Polyamine contents can change under some conditions, such as tissue regeneration, diabetes and growth (Grillo & Bedino, 1977;Grillo et al, 1978a,b;Grillo & Pezzali, 1984;Corti et al, 1985), but, apart from increases in putrescine, insulin does not appear to cause very marked changes in the cellular contents of the major polyamines (Grillo et al, 1978a,b;Brosnan & Hu, 1983). In contrast with this, two key enzymes involved in polyamine biosynthesis, ornithine decarboxylase and S-adenosylmethionine decarboxylase, can be induced by several-fold subsequent to insulin treatment.…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of pyruvate dehydrogenase phosphate phosphatase to magnesium ions. Similar effects of spermine and insulin

Thomas

Diggle²,

Denton³

1986

Biochemical Journal

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The effects of Mg2+ on the activity of pyruvate dehydrogenase phosphate phosphatase within intact mitochondria prepared from control and insulin-treated rat epididymal adipose tissue was explored by incubating the mitochondria in medium containing the ionophore A23187. The apparent Ka for Mg2+ was approximately halved in the mitochondria derived from insulin-treated tissue in both the absence and the presence of Ca2+. In this system, the major effect of Ca2+ was also to decrease the apparent Ka for Mg2+, rather than to change the Vmax. of the phosphatase. Damuni, Humphreys & Reed [(1984) Biochem. Biophys. Res. Commun. 124, 95-99] have reported that spermine activates ox kidney pyruvate dehydrogenase phosphate phosphatase. Studies were carried out on phosphatase from pig heart and rat epididymal adipose tissue which confirm and extend this observation. The major effect of spermine is shown to be a decrease in the Ka for Mg2+, which is apparent in both the presence and the absence of Ca2+. Spermine did not affect the sensitivity of the phosphatase to Ca2+ at saturating concentrations of Mg2+. Other polyamines tested were not as effective as spermine. No alteration in the maximum activity or Mg2+-sensitivity of pyruvate dehydrogenase phosphate phosphatase was apparent in extracts of mitochondria from insulin-treated tissue. The close similarity of the effects of spermine and the changes in kinetic properties of pyruvate dehydrogenase phosphate phosphatase within mitochondria from insulin-treated adipose tissue suggests that insulin may activate pyruvate dehydrogenase by increasing the concentration of spermine within the mitochondria. However, it is concluded that insulin is more likely to alter the interaction of the pyruvate dehydrogenase system with some other polybasic intramitochondrial component whose action can be mimicked by spermine.

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Section: Discussionmentioning

confidence: 99%

Sensitivity of pyruvate dehydrogenase phosphate phosphatase to magnesium ions. Similar effects of spermine and insulin

Thomas

Diggle²,

Denton³

1986

Biochemical Journal

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“…3). Based on results in several previous studies (12‐15) in which investigators measured the levels of polyamines present in milk, human and rat milk have total polyamine concentrations of approximately 1 to 7.3 × 10 ‐5 M. After the 1:20 dilution of milk in the culture medium (5% vol/vol) used in our experiments, the concentration of polyamine present in the culture medium based on these estimates (0.5 to 3.7 × 10 ‐6 M) would be in the range expected to support IEC‐6 cell growth in the presence of DFMO inhibition. Although bovine milk has been reported to contain polyamines in amounts similar to those in rat and human milk, the bovine milk used in the present experiments did not have sufficient bioactive polyamine to reverse the inhibition imposed by DFMO.…”

Section: Discussionmentioning

confidence: 67%

“…Intestinal epithelial cells are exposed to several sources of polyamines, including those derived from the diet (9), synthesized by microflora(10), secreted in bile (11), and derived from dead cells (6). Polyamines have been identified and measured in human, rat, and bovine milk and in infant formulas(12‐16). In the current study, we tested whether the polyamines present in maternal milk from different animal species and infant formula (12‐16) were of sufficient quantity and bioactivity to support growth of a nontransformed rat intestinal cell line during inhibition of endogenous polyamine synthesis by difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase (the rate‐limiting enzyme in polyamine synthesis) (6).…”

mentioning

confidence: 99%

Polyamines in Human and Rat Milk Influence Intestinal Cell Growth In Vitro

Capano,

Bloch,

Carter

et al. 1998

J. pediatr. gastroenterol. nutr.

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Background:Polyamines are required for intestinal growth and development. In this study, we examined whether milk can supply the polyamines needed for growth of IEC‐6 cells, a line on non‐transformed rat intestinal crypt cells.Methods:Human, bovine, and rat milk, and cow's milk‐based infant formula were studied. Human, bovine, and rat milk were defatted and sterilized by filtration. IEC‐6 cells were stabilized in Dulbecco's modified Eagle's medium(DMEM) containing 0.5% fetal bovine serum, 5 mM L‐glutamine, 100 U/mL penicillin and 100 µg/mL streptomycin for 24 h at 37°C. Thereafter, to initiate active growth, cells were placed in fresh DMEM containing 5% FBS(plus the other ingredients) supplemented with 5% (vol/vol) milk or infant formula. In some experiments, cells were also treated with difluoromethylornithine (2.5 mM) (DFMO), an inhibitor of polyamine synthesis, or dialyzed milk plus DFMO. After 44 hours of culture, cells were pulsed with3 H‐thymidine (3H‐TdR) for 4 hours, harvested and the radioactivity incorporated into DNA was measured.Results:Human and rat milk stimulated proliferation of IEC‐6 cells (p < 0.05 compared to controls); addition of DFMO did not reverse the stimulatory effect. Bovine milk and the infant formula did not stimulate proliferation or prevent the growth inhibition induced by DFMO. After dialysis, human milk had less ability to reverse the DFMO inhibition (p < 0.05).Conclusions:These experiments suggest that both human and rat milk, but neither bovine milk nor the infant formula, contain sufficient bioactive polyamines to sustain cell growth during inhibition of polyamine synthesis.

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“…Thus, the dose of spermidine given to induce maturation in the present experiment approximates a physiologic dose for a 23-day-old rat. Based on the assumptions that the polyamine content of rat milk is approximately 10 to 45 nmol of polyamine/ml, with spermidine predominating (19)(20)(21), and that the neonate ingests several milliliters per day, the total amount ingested by the neonate is estimated to be about 40 to 180 nmol/day (based on an estimated 4 ml/day of breast milk). This dose of polyamine appears to be insufficient to stimulate maturation in the 6-to 10-day-old neonate.…”

Section: Discussionmentioning

confidence: 99%

“…The relative importance of luminal uptake of polyamines versus endogenous synthesis has not been established, but studies have suggested that dietary polyamines can enhance mucosal growth in normal rats (18), promote healing of mucosal injury in "stressed animals" (22), and accelerate maturation of intestinal mucosa in neonatal rats (23)(24)(25). Rat and human milk, rat chow, and infant formulas all contain detectable amounts of polyamines (19)(20)(21); the highest levels were found in rat chow. Rat and human milk contained an approximately 10-fold lower amount of polyamine.…”

mentioning

confidence: 99%

Influence of the Polyamine, Spermidine, on Intestinal Maturation and Dietary Antigen Uptake in the Neonatal Rat

Capano,

Bloch,

Schiffrin

et al. 1994

J. pediatr. gastroenterol. nutr.

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SummaryPolyamines appear to have an important role in postnatal growth of the rat intestine. In the present study, we examined the effect of spermidine on the maturation of the intestine and on its ability to exclude macromolecules. Two litters of Sprague‐Dawley rat pups were assigned to one of four experimental groups. These groups received, on Days 7, 8, and 9, either (a) saline by gavage; (b) spermidine, 0.9 mg (6 μmol) by gavage; (c) cortisone acetate, 3.5 mg i.p.; or (d) saline i.p. On Day 10, animals were fed by gavage with a mixture of bovine serum albumin (BSA; 2 mg/g) and the γ‐globulin fraction of mouse antiovalbumin (anti‐OVA) antiserum (1 mg/g) and were bled 4 h later. Intestinal tissues were processed for histologic examination, sucrase determination, and identification of neonatal intestinal Fc receptor (FcRn) by Western blot. Serum immunoreactive BSA (iBSA) and mouse IgG1 and IgG2a anti‐OVA antibodies were estimated by enzyme‐linked immunosorbent assay. Sucrase activity was elevated in cortisone‐ and spermidine‐treated compared to control rats. iBSA and anti‐OVA were significantly reduced in cortisone‐treated compared to control rats but were not diminished significantly in the spermidine‐treated animals. A decrease in the neonatal intestinal Fc receptor was apparent in the spermidine‐fed group; cortisone produced a large reduction in FcRn. Spermidine‐fed animals showed morphologic evidence of maturation, with loss of giant vacuoles in the distal intestine; cortisone did not produce significant changes in morphology. Thus, while spermidine, like cortisone, enhanced the appearance of the disaccharidase sucrase, it did not significantly reduce the uptake of BSA or IgG, which is usually observed in mature compared to immature animals. The reason for this dichotomy is not known.

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Ornithine Decarboxylase Antizyme in Mammalian Tissues

Cited by 5 publications

References 24 publications

Sensitivity of pyruvate dehydrogenase phosphate phosphatase to magnesium ions. Similar effects of spermine and insulin

Sensitivity of pyruvate dehydrogenase phosphate phosphatase to magnesium ions. Similar effects of spermine and insulin

Polyamines in Human and Rat Milk Influence Intestinal Cell Growth In Vitro

Influence of the Polyamine, Spermidine, on Intestinal Maturation and Dietary Antigen Uptake in the Neonatal Rat

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