scholarly journals Involvement of calcium ions in the activation of ornithine decarboxylase by isoprenaline evaluated ‘in situ’ in the perfused rat heart

1983 ◽  
Vol 212 (1) ◽  
pp. 241-243 ◽  
Author(s):  
C Guarnieri ◽  
F Flamigni ◽  
C Muscari ◽  
C M Caldarera
Keyword(s):  
Ornithine Decarboxylase ◽  
Calcium Ions ◽  
Decarboxylase Activity ◽  
Ionophore A23187 ◽  
Perfusion Medium ◽  
Perfused Rat Heart ◽  
Ornithine Decarboxylase Activity ◽  
Rat Hearts ◽  
Perfused Hearts

Ornithine decarboxylase activity evaluated during the perfusion of isolated rat hearts by a method ‘in situ’ was rapidly increased when the hearts were infused with isoprenaline (isoproterenol). Omission of Ca2+ from the perfusion medium or the administration of verapamil to the perfused hearts decreased the isoprenaline-stimulated ornithine decarboxylase activity, whereas a marked stimulatory effect was registered when the hearts were perfused with the Ca2+ ionophore A23187.

scholarly journals Role of calcium in the modulation of ornithine decarboxylase activity in isolated pig granulosa cells in vitro

1981 ◽  
Vol 196 (3) ◽  
pp. 795-801 ◽  
Author(s):  
Johannes D. Veldhuis ◽  
James M. Hammond
Keyword(s):  
Cyclic Amp ◽  
Ornithine Decarboxylase ◽  
Granulosa Cells ◽  
Phosphodiesterase Inhibitor ◽  
Decarboxylase Activity ◽  
Ionophore A23187 ◽  
Bivalent Cation ◽  
Ornithine Decarboxylase Activity

We examined the role of Ca2+ in the control of basal and hormone-stimulated ornithine decarboxylase activity in isolated pig granulosa cells maintained under chemically defined conditions in vitro. Omission of Ca2+ from the incubation medium (measured Ca2+ concentration 5μm) decreased basal enzymic activity, and significantly (P<0.01) impaired the response to maximally stimulating doses of either lutropin or follitropin. No significant alteration occurred in the concentration of either gonadotropin required to elicit half-maximal effects. The addition of EGTA (1.27–2.0mm) to chelate residual extracellular Ca2+ further decreased hormone-induced rises in ornithine decarboxylase activity. Despite the presence of 1.27mm concentrations of extracellular Ca2+, the administration of presumptive Ca2+ antagonists, believed to impair trans-membrane Ca2+ influx [verapamil (10–100μm), nifedipine (1–100μm) or CoCl2 (1mm)] suppressed hormone-stimulated ornithine decarboxylase activity. The inhibitory effects of verapamil or of Ca2+ omission from the medium were not overcome by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (0.25mm), or by cholera toxin, or by an exogenously supplied cyclic AMP analogue, 8-bromo cyclic AMP. Conversely, micromolar concentrations of a putative bivalent-cation ionophore, A23187, increased significantly the stimulation of ornithine decarboxylase activity by saturating concentrations of lutropin or 8-bromo cyclic AMP. Thus the present observations implicate Ca2+ ions in the modulation of hormone action and cellular function in normal ovarian cells.

scholarly journals Difluoromethylornithine irreversibly inactivates ornithine decarboxylase of Pseudomonas aeruginosa, but does not inhibit the enzymes of Escherichia coli

1981 ◽  
Vol 200 (1) ◽  
pp. 69-75 ◽  
Author(s):  
A Kallio ◽  
P P McCann
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Ornithine Decarboxylase ◽  
Arginine Decarboxylase ◽  
Decarboxylase Activity ◽  
Dependent Manner ◽  
Irreversible Inhibitor ◽  
E Coli ◽  
Ornithine Decarboxylase Activity

DL-alpha-Difluoromethylornithine, an enzyme-activated irreversible inhibitor of eukaryotic ornithine decarboxylase and consequently of putrescine biosynthesis, inhibited ornithine decarboxylase in enzyme extracts from Pseudomonas aeruginosa in a time-dependent manner t1/2 1 min, and also effectively blocked the enzyme activity in situ in the cell. Difluoromethylornithine, however, had no effect on the activity of ornithine decarboxylase assayed in enzyme extracts from either Escherichia coli or Klebsiella pneumoniae. However, the presence of the inhibitor in cell cultures did partially lower ornithine decarboxylase activity intracellularly in E. coli. Any decrease in the intracellular ornithine decarboxylase activity observed in E. coli and Pseudomonas was accompanied by a concomitant increase in arginine decarboxylase activity, arguing for a co-ordinated control of putrescine biosynthesis in these cells.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

scholarly journals ORNITHINE DECARBOXYLASE ACTIVITY AS A PROGNOSTIC MARKER FOR COLORECTAL CANCER

2007 ◽  
Vol 53 (1) ◽  
pp. 1-9 ◽  
Author(s):  
YUTAKA HOSHINO ◽  
SHINYA TERASHIMA ◽  
YASUSHI TERANISHI ◽  
MASANORI TERASHIMA ◽  
MICHIHIKO KOGURE ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Prognostic Marker ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity
Sign in / Sign up

Export Citation Format

Share Document