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Solid-phase extraction of plasma vasopressin: evaluation, validation and application
B J Van de Heijning1, I Koekkoek-van den Herik, T Iványi
1Department of Pharmacology, Rudolf Magnus Institute, University of Utrecht, The Netherlands.
Journal of Chromatography
|April 19, 1991
Summary
A new solid-phase extraction method accurately measures vasopressin levels in rat plasma. This technique reveals how dehydration, water loading, and ethanol affect vasopressin-like immunoreactivity, aiding in understanding fluid balance regulation.
Area of Science:
- Endocrinology
- Analytical Chemistry
- Pharmacology
Background:
- Vasopressin (antidiuretic hormone) plays a crucial role in regulating water balance.
- Accurate measurement of vasopressin in biological samples is essential for physiological and pharmacological studies.
- Existing methods for vasopressin extraction and quantification can be complex and time-consuming.
Purpose of the Study:
- To develop and validate a novel solid-phase extraction (SPE) method for quantifying vasopressin-like immunoreactivity in rat plasma.
- To assess the impact of physiological challenges on plasma vasopressin levels using the developed method.
Main Methods:
- Solid-phase extraction using octyl-silica columns for plasma sample preparation.
- Radioimmunoassay (RIA) for the quantification of extracted vasopressin.
- Reversed-phase high-performance liquid chromatography (RP-HPLC) for confirmation of identity.
- Validation of the method using synthetic vasopressin and rat plasma.
Main Results:
- The developed SPE-RIA method demonstrated high recovery (ca. 100%) and specificity for vasopressin.
- The method achieved a detection limit of 1 fmol/mL with acceptable intra- and inter-assay variability (10-16% and 16%, respectively).
- Osmotic challenge and dehydration significantly increased plasma vasopressin, while ethanol ingestion decreased it.
Conclusions:
- A robust and reliable SPE-RIA method for vasopressin measurement in rat plasma has been established.
- The method accurately reflects changes in vasopressin levels under various physiological conditions.
- This technique provides a valuable tool for investigating the neuroendocrinology of water homeostasis.