| Autor: |
Silveira, P.F., Koike, T.I., Schiripa, L.N., Reichl, A.P., Magnoli, F.C., Mimura, O.M. |
| Zdroj: |
General and Comparative Endocrinology; March 1998, Vol. 109 Issue: 3 p336-346, 11p |
| Abstrakt: |
Peaks corresponding to arg-vasotocin obtained by HPLC from Sep-Pak C18 column extracts ofBothrops jararacaplasma were identified by radioimmunoassay and amino acid analysis. Plasma vasotocin and protein levels, osmolality, andl-cystine-di-β-naphthylamidase were also compared in snakes under normal hydration conditions with or without chronic administration of vasotocin or in the presence of chronic hydroosmotic challenges. Sep-Pak C18 and radioimmunoassay were validated for the extraction and determination of this peptide, respectively (about 80% recovery). EDTA presented a protective action on this recovery compared to the use of heparin as anticoagulant for snake blood. A reduction of vasotocin content related to the time of incubation of this peptide added to snake plasma was detected by radioimmunoassay. Snake plasma activity also onl-cystine-di-β-naphthylamide indicated that this vasotocin-destroying effect was due to hydrolysis by a cystine-aminopeptidase-like activity. Plasma levels of vasotocin revealed an unexpected dispersion and absent correlation with plasma levels of osmolality. Measurable vasotocin in a large number of snakes associated with lower levels ofl-cystine-di-β-naphthylamidase in acute than in chronic salt loading suggested the role of this enzyme activity in long-term regulation of the vasotocin system in this snake. |
| Databáze: |
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