Different biochemical strategies of two Neotropical fish to cope with the impairment of nitrogen excretion during air exposure
AUTOR(ES)
Polez, V.L.P., Moraes, G., Santos Neto, C.
FONTE
Brazilian Journal of Medical and Biological Research
DATA DE PUBLICAÇÃO
2003-02
RESUMO
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, µmol min-1 g protein-1) of H. malabaricus showed significant increases (P<0.05, 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.
Documentos Relacionados
- Biochemical and genetic alterations in the freshwater neotropical fish Prochilodus lineatus after acute exposure to Microcystis aeruginosa
- Living with digestive stomas: strategies to cope with the new bodily reality
- Biochemical biomarkers of exposure to deltamethrin in freshwater fish, Ancistrus multispinis
- DIFFERENT RESPONSE TO EXPOSURE TO AIR POLLUTANTS IN GIRLS AND BOYS
- Evaluation of nutrient excretion and retention in broilers submitted to different nutritional strategies