Different biochemical strategies of two neotropical fish to cope with the impairment of nitrogen excretion during air exposure
| Autor: | C. Santos Neto, V.L.P. Polez, Gilberto Moraes |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
medicine.medical_specialty
Physiology Nitrogen Immunology Biophysics Biochemical adaptation Biochemistry Hoplias malabaricus Excretion chemistry.chemical_compound Ammonia Urea cycle enzymes Species Specificity Glutamate-Ammonia Ligase Internal medicine Glutamine synthetase medicine Animals Urea General Pharmacology Toxicology and Pharmaceutics lcsh:QH301-705.5 Ornithine Carbamoyltransferase Hoplerythrinus unitaeniatus lcsh:R5-920 biology Arginase General Neuroscience Air Fishes Cell Biology General Medicine Ornithine biology.organism_classification Uric Acid Endocrinology Fish chemistry lcsh:Biology (General) Air exposure Uric acid lcsh:Medicine (General) Biomarkers |
| Zdroj: | Brazilian Journal of Medical and Biological Research, Vol 36, Iss 2, Pp 279-285 (2003) Brazilian Journal of Medical and Biological Research, Volume: 36, Issue: 2, Pages: 279-285, Published: FEB 2003 Brazilian Journal of Medical and Biological Research v.36 n.2 2003 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC |
| ISSN: | 0100-879X |
| Popis: | The exposure of fish to air is normally expected to interfere with the nitrogen excretion process. Hoplias malabaricus and Hoplerythrinus unitaeniatus, two teleost species, display distinct behaviors in response to decreases in natural reservoir water levels, although they may employ similar biochemical strategies. To investigate this point, plasma levels of ammonia, urea, uric acid, and the two urea cycle enzymes, ornithine carbamoyl transferase (OCT) and arginase (ARG), as well as glutamine synthetase (GS) were determined for both species after exposure to air. Plasma ammonia increased gradually during exposure to air, but only H. malabaricus showed increased concentrations of urea. Plasma uric acid remained very low in both fish. Enzymatic activities (mean +/- SD, micromol min(-1) g protein(-1)) of H. malabaricus showed significant increases (P0.05, N = 6) in OCT from 0.84 +/- 0.05 to 1.42 +/- 0.03, in ARG from 8.07 +/- 0.47 to 9.97 +/- 0.53 and in GS from 1.15 +/- 0.03 to 2.39 +/- 0.04. The OCT and ARG enzymes remained constant in H. unitaeniatus (N = 6), but GS increased from 1.49 +/- 0.02 to 2.06 +/- 0.03. Although these species are very closely related and share the same environment, their biochemical strategies in response to exposure to air or to increased plasma ammonia are different. |
| Databáze: | OpenAIRE |
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