Further Characterization of the Endogenous Natriuretic and Digoxin-Like Immunoreacting Activities in Human Urine: Effects of Changes in Sodium Intake
| Autor: | Herbert J. Kramer, Dietrich Klingmüller, Marita Heppe, Colin Dr. Liddiard, Angela Bäcker, Elmar Weiler |
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| Rok vydání: | 1985 |
| Předmět: |
Adult
Male Digoxin medicine.medical_specialty Time Factors Size-exclusion chromatography Radioimmunoassay Natriuresis Endogeny Urine Sodium Chloride Antibodies Internal medicine Mole medicine Animals Humans Bioassay chemistry.chemical_classification Chromatography Chemistry General Medicine Diet Sodium-Restricted Chromatography Ion Exchange Precipitin Tests Rats Amino acid Proteinuria Endocrinology Nephrology Chromatography Gel Biological Assay Female Natriuretic Agents Cardiology and Cardiovascular Medicine medicine.drug |
| Zdroj: | Kidney and Blood Pressure Research. 8:80-89 |
| ISSN: | 1423-0143 1420-4096 |
| DOI: | 10.1159/000173039 |
| Popis: | In the present study natriuretic activity and digoxin-like immunoreacting activity (DLIA) were determined in small molecular weight (MW) fractions of urine from healthy subjects during low (35 mmol/day) and high ( > 400 mmol/day) sodium intake by bioassay and by a radioimmunoassay for digoxin, respectively. After gel filtration of urine on a Sephadex®G-25 column the natriuretic activity appeared in the post-salt fraction SIV, whereas DLIA was present in small amounts in the salt fraction SIII and, with consistently higher activity, in the post-salt fraction SIV. Natriuretic activity significantly increased and DLIA decreased in fraction SIV with high sodium intake, but total urinary excretion of DLIA remained unaltered during changes in sodium intake. In addition, anion-exchange and reverse-phase chromatography revealed that DLIA is not specifically related to the natriuretic activity but also reflects unspecific binding of various urine constituents to this digoxin antibody. Although the antibody binds a natriuretic material, this radioimmunoassay is thus unsuitable to determine the endogenous natriuretic activity in urine fractions. Whereas they elute differently on reverse-phase chromatography, amino acid analyses revealed that both the natriuretic factor directly purified from the post-salt fraction SIV and the natriuretic material bound to the digoxin antibody have in common four amino acids at similar molar ratios. The physicochemical properties as evidenced by chromatographic and electrophoretic studies as well as enzymatic inactivation suggest that the low MW natriuretic factor(s) in human urine may be associated with a small peptide(s) of weak acidic nature. |
| Databáze: | OpenAIRE |
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