scholarly journals Ornithine decarboxylase activity during development of the mouse inner ear in vivo and in vitro

1991 ◽  
Vol 265 (3) ◽  
pp. 547-550 ◽  
Author(s):  
Sherry A. Crann ◽  
Thomas R. Van de Water ◽  
Jochen Schacht
Keyword(s):  
Inner Ear ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity

scholarly journals Role of pyridoxal phosphate in mammalian polyamine biosynthesis. Lack of requirement for mammalian S-adenosylmethionine decarboxylase activity

1977 ◽  
Vol 166 (1) ◽  
pp. 81-88 ◽  
Author(s):  
A E Pegg
Keyword(s):  
Ornithine Decarboxylase ◽  
Pyridoxal Phosphate ◽  
Vitamin B ◽  
Decarboxylase Activity ◽  
Deficient Diet ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Ornithine Decarboxylase Activity

1. Polyamine concentrations were decreased in rats fed on a diet deficient in vitamin B-6. 2. Ornithine decarboxylase activity was decreased by vitamin B-6 deficiency when assayed in tissue extracts without addition of pyridoxal phosphate, but was greater than in control extracts when pyridoxal phosphate was present in saturating amounts. 3. In contrast, the activity of S-adenosylmethionine decarboxylase was not enhanced by pyridoxal phosphate addition even when dialysed extracts were prepared from tissues of young rats suckled by mothers fed on the vitamin B-6-deficient diet. 4. S-Adenosylmethionine decarboxylase activities were increased by administration of methylglyoxal bis(guanylhydrazone) (1,1′-[(methylethanediylidine)dinitrilo]diguanidine) to similar extents in both control and vitamin B-6-deficient animals. 5. The spectrum of highly purified liver S-adenosylmethionine decarboxylase did not indicate the presence of pyridoxal phosphate. After inactivation of the enzyme by reaction with NaB3H4, radioactivity was incorporated into the enzyme, but was not present as a reduced derivative of pyridoxal phosphate. 6. It is concluded that the decreased concentrations of polyamines in rats fed on a diet containing vitamin B-6 may be due to decreased activity or ornithine decarboxylase or may be caused by an unknown mechanism responding to growth retardation produced by the vitamin deficiency. In either case, measurements of S-adenosylmethionine decarboxylase and ornithine decarboxylase activity under optimum conditions in vitro do not correlate with the polyamine concentrations in vivo.

scholarly journals Diamine-induced inhibition of liver ornithine decarboxylase

1979 ◽  
Vol 177 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Arja Kallio ◽  
Monica Löfman ◽  
Hannu Pösö ◽  
Juhani Jänne
Keyword(s):  
Enzyme Activity ◽  
Ornithine Decarboxylase ◽  
Enzyme Inhibitor ◽  
Decarboxylase Activity ◽  
Enzyme Protein ◽  
Intracellular Degradation ◽  
Ornithine Decarboxylase Activity ◽  
Normal Rat

Re!peated injections of 1,3-diaminopropane, a potent inhibitor of mammalian ornithine decarboxylase, induced protein-synthesis-dependent formation of macromolecular inhibitors or ‘antienzymes’ [Heller, Fong & Canellakis (1976) Proc. Natl. Acad. Sci. U.S.A.73, 1858–1862] to ornithine decarboxylase in normal rat liver. Addition of the macromolecular inhibitors, produced in response to repeated injections of diaminopropane, to active ornithine decarboxylase in vitro resulted in a profound loss of the enzyme activity, which, however, could be partly recovered after passage of the enzyme–inhibitor mixture through a Sephadex G-75 columin in the presence of 0.4m-NaCl. This treatment also resulted in the appearance of free inhibitor. In contrast with the separation of the enzyme and inhibitory activity after combination in vitro, it was not possible to re-activate, by using identical conditions of molecular sieving, any inhibited ornithine decarboxylase from cytosol fractions obtained from animals injected with diaminopropane. However, the idea that injection of various diamines, also in vivo, induces acute formation of macromolecular inhibitors, which reversibly combine with the enzyme, was supported by the finding that the ornithine decarboxylase activity remaining after diaminopropane injection appeared to be more stable to increased ionic strength than the enzyme activity obtained from somatotropin-treated rats. Incubation of the inhibitory cytosol fractions with antiserum to ornithine decarboxylase did not completely abolish the inhibitory action of either the cytosolic inhibitor or the antibody. A single injection of diaminopropane produced an extremely rapid decay of liver ornithine decarboxylase activity (half-life about 12min), which was comparable with, or swifter than, that induced by cycloheximide. However, although after cycloheximide treatment the amount of immunotitrable ornithine decarboxylase decreased only slightly more slowly than the enzyme activity, diaminopropane injection did not decrease the amount of the immunoreactive protein, but, on the contrary, invariably caused a marked increase in the apparent amount of antigen, after some lag period. The diamine-induced increase in the amount of the immunoreactive enzyme protein could be totally prevented by a simultaneous injection of cycloheximide. These results are in accord with the hypothesis that various diamines may result in rapid formation of macromolecular inhibitors to ornithine decarboxylase in vivo, which, after combination with the enzyme, abolish the catalytic activity but at the same time prevent the intracellular degradation of the enzyme protein.

EARLY INHIBITION BY PROGESTERONE OF OESTROGEN-INDUCED ORNITHINE DECARBOXYLASE ACTIVITY IN THE CHICK OVIDUCT AND RAT UTERUS

1981 ◽  
Vol 90 (1) ◽  
pp. 1-7 ◽  
Author(s):  
CARLOS LEVY ◽  
JAN MEŠTER ◽  
ETIENNE-EMILE BAULIEU
Keyword(s):  
Ornithine Decarboxylase ◽  
Maximum Level ◽  
Decarboxylase Activity ◽  
Rat Uterus ◽  
Ornithine Decarboxylase Activity ◽  
Oestradiol Benzoate ◽  
Early Inhibition

The oestradiol-induced increase of ornithine decarboxylase (ODC) activity in the 'withdrawn' chick oviduct was found to be inhibited by progesterone. In vitro (2 h at 37 °C), progesterone (1 μmol/l) abolished the effect of oestradiol (20 nmol/l), progesterone alone having no effect. In vivo, progesterone (3 mg/kg) inhibited ∼70% of the augmentation of ODC activity induced in the oviduct within 2 to 6 h of treatment with oestradiol benzoate (1·5 mg/kg). Administration of progesterone alone in vivo caused an increase in the ODC activity, the maximum level measured after 6 h being similar to that obtained when the chicks were given both oestrogen and progesterone. In the rat uterus in vivo progesterone also inhibited the rise of ODC activity caused by oestradiol, ∼70% inhibition being observed between 2 and 6 h after treatment. Progesterone alone had no effect on uterine ODC activity during this period.

scholarly journals Amine-specificity of the inactivating ornithine decarboxylase modification in Physarum polycephalum

1982 ◽  
Vol 205 (3) ◽  
pp. 551-557 ◽  
Author(s):  
J L A Mitchell ◽  
G K Mitchell ◽  
D D Carter
Keyword(s):  
Ornithine Decarboxylase ◽  
Translational Control ◽  
Feedback Mechanism ◽  
Decarboxylase Activity ◽  
Polyamine Biosynthesis ◽  
Polyamine Analogues ◽  
Ornithine Decarboxylase Activity ◽  
Sensitivity Studies

The enzyme catalysing the polyamine-stimulated modification of Physarum ornithine decarboxylase in vivo was partially purified and its activity on purified ornithine decarboxylase was examined with respect to its specificity for various amines. Spermidine, spermine and several polyamine analogues strongly promoted this reaction in vitro (apparent Km in the 0.1-0.5 mM range), whereas putrescine (apparent Km 5.33 mM) and several related diamines were not nearly as effective. In agreement with this, sensitivity studies performed in vivo also suggested that cellular spermidine, and not putrescine, is critical in modulating ornithine decarboxylase activity by this post-translational control. Unlike putrescine, or other diamines, 1,3-diaminopropane demonstrated a functional similarity to the polyamines in stimulating this reaction. This study has demonstrated a method whereby non-physiological amines capable of depressing ornithine decarboxylase activity by this natural feedback mechanism can be readily identified for further evaluation of their potential use in the experimental and medical control of polyamine biosynthesis.

scholarly journals The role of polyamine biosynthesis in hematopoietic precursor cell proliferation in mice

Blood ◽  
1983 ◽  
Vol 61 (4) ◽  
pp. 740-745 ◽  
Author(s):  
E Niskanen ◽  
A Kallio ◽  
PP McCann ◽  
DG Baker
Keyword(s):  
Ornithine Decarboxylase ◽  
Colony Formation ◽  
Calf Serum ◽  
Decarboxylase Activity ◽  
Irreversible Inhibitor ◽  
Host Animal ◽  
Polyamine Biosynthesis ◽  
Diffusion Chambers

Abstract Under the influence of a selective irreversible inhibitor of ornithine decarboxylase (ODC), DL-alpha-difluoromethylornithine (DFMO), early hematopoiesis was enhanced. In the bone marrow, the absolute number of cells that give rise to spleen colonies in lethally irradiated mice (CFU-S), granulocytic colonies in diffusion chambers in mice (CFU-DG), and granulocyte-monocyte colonies in agar in vitro (CFU-C) was increased 2–4 fold. This could be abrogated by administration of putrescine, confirming the association of the stimulatory effect with polyamine biosynthesis most likely via depression of ornithine decarboxylase activity and subsequent synthesis of putrescine. Analysis of cell cycle characteristics by 3H-TdR suicide technique demonstrated that the proportion of CFU-S, CFU-DG, and CFU-C in S-phase was significantly increased. Additionally, the stimulatory effect was reflected by enhanced colony formation in diffusion chambers implanted intraperitoneally in mice receiving DFMO. This could also be eliminated by treatment of the host animal with putrescine, again suggesting that polyamine biosynthesis plays an important role at the early stages of hematopoiesis in vivo. Effect of DFMO on colony formation in vitro (CFU- C) was inhibitory and not reversible with putrescine. It could be partially eliminated by aminoguanidine, which neutralizes diamine oxidase present in fetal calf serum used in the CFU-C assay. These data suggest that the effect of DFMO in vitro was nonspecific.

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