Urinary and plasma urodilatin measured by a direct RIA using a highly specific antiserum

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 44; no. 12; pp. 2524 - 2529
• Main Authors: Meyer, Markus, Armbruster, Franz P, Maier, Ina, Schwing, Jens, Haller, Christlieb, Missbichler, Albert, Adermann, Knut, Forssmann, Wolf-Georg, Woloszczuk, Wolfgang
• Format: Journal Article
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.12.1998; American Association for Clinical Chemistry
• Subjects: Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Animals; Antibody Specificity; Asthma - drug therapy; Asthma - metabolism; Atrial Natriuretic Factor - analysis; Atrial Natriuretic Factor - blood; Atrial Natriuretic Factor - immunology; Atrial Natriuretic Factor - urine; Biological and medical sciences; Bronchodilator Agents - analysis; Bronchodilator Agents - blood; Bronchodilator Agents - immunology; Bronchodilator Agents - urine; Cardiac Catheterization; Diuretics - analysis; Diuretics - blood; Diuretics - immunology; Diuretics - urine; Fundamental and applied biological sciences. Psychology; Immune Sera; Infusions, Intravenous; Male; Peptide Fragments - analysis; Peptide Fragments - blood; Peptide Fragments - immunology; Peptide Fragments - urine; Proteins; Rabbits; Radioimmunoassay; Sheep; Sodium, Dietary - administration & dosage; Human; Urine; Biological fluid; Natriuretic hormone; Analog; Radioimmunoassay; Peptide hormone; Atrial natriuretic peptide; Immunological method; Quantitative analysis; Blood plasma
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/44.12.2524

Urodilatin (95-126) (URO) appears to play a major physiologic role in fluid homeostasis and produces major changes when administered intravenously. Here we describe a monospecific, high-affinity antiserum against URO with no cross-reactivity (<0.01%) against the structural highly homologous atrial natriuretic peptide 99-126 (ANP-99-126), ANP analogs, and related peptides such as brain natriuretic peptide. A competitive RIA was developed, based on this antiserum. Urine samples with or without ethanol extraction and plasma samples without pretreatment were analyzed by the RIA, which had a detection limit of 10.5 ng/L, a linear measuring range between 10.5 and 1000 ng/L, and recoveries of 93-102% in urine and 90-104% in plasma. The intraassay CVs were 8.2% and 8.1% for urine samples with 269 and 669 ng/L URO; the interassay CV was 9.7% at 839 ng/L. Using this assay, we present URO data for urine from healthy volunteers receiving low and routine sodium diets and from clinical urine specimens; we also present pharmacokinetic data for URO in plasma from patients suffering from bronchial asthma and treated by URO infusion.