Abstract
L-Asparagine stimulates bi-directional Ca2+ flows and induces ornithine decarboxylase in Reuber H-35 hepatoma cells. Previously it has been shown that these effects are completely, but reversibly inhibited by lanthanum chloride. In this study we examined the role(s) of Ca2+ flows using more specific Ca2+ flow inhibitors. It was shown that ornithine decarboxylase induction was inhibited by CdCl2, and verapamil at concentrations above 1 μM and 100 μM respectively, but was unaffected by as much as 300 μM NiCl2, 1 mM nifedipine, or 10 μM ω-conotoxin. Enzyme induction was blocked by the Ca2+-ATPase pump antagonists vanadate and Compound 48/80 in a dose-dependent manner. These results, taken together with the observations that extracellular Ca2+ is essential for enzyme induction but a substantial elevation of cytoplasmic [Ca2+] is not, suggest that Ca2+ inflow independent of the receptor-activated Ca2+ channels, and the Ca2+ ATPase mediated Ca2+ out-flow, are both important factors in the action of L-asparagine.
Original language | English |
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Pages (from-to) | 1041-1047 |
Number of pages | 7 |
Journal | Biochemistry and Molecular Biology International |
Volume | 38 |
Issue number | 5 |
Publication status | Published - 1996 |
Scopus Subject Areas
- Biochemistry
- Molecular Biology
- Genetics
User-Defined Keywords
- ω-conotoxin
- Ca
- Cd
- Compound 40/80
- H-35 cells
- L-asparagine
- Ni
- Nifedipine
- Ornithine decarboxylase
- Vanadate
- Verapamil