Development of a homologous equine relaxin radioimmunoassay.
Abstract: Equine relaxin (eRlx) immunoactivity has previously been measured in the mare during pregnancy using the porcine relaxin (pRlx) RIA (pRlx-RIA). This was not the optimal system for measurement of eRlx because the dose-response curve obtained with equine plasma was not parallel to the pRlx standard curve. A homologous eRlx-RIA has been developed and used to measure relaxin immunoactivity during pregnancy and parturition in the mare. Highly purified eRlx was used for the generation of antiserum in rabbits, preparation of tracer, and as assay standards. A double antibody eRlx RIA (eRlx-RIA) was developed which was highly specific and sensitive (0.023 ng relaxin/tube). The dose-response curve obtained with eRlx plasma was parallel to the equine standard curve while there was no parallelism noted between the pRlx and eRlx standard curves. This assay was utilized to measure eRlx in samples collected during pregnancy which were previously measured for relaxin content in the pRlx-RIA. It was found that the two assay systems gave almost identical patterns of secretion throughout pregnancy. The two assays differed in the amount of relaxin measured, with the eRlx-RIA measuring considerably higher amounts during gestation than the pRlx assay. In oxytocin-induced foalings, the differences became greater with the equine assay measuring as much as 10-fold greater concentrations.
Publication Date: 1986-09-01 PubMed ID: 3732158DOI: 10.1210/endo-119-3-1100Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This study involved the development of a more accurate equine relaxin radioimmunoassay, a test used to measure the hormone relaxin in pregnant mares. This new assay provided significantly different results from the previously used porcine relaxin assay, suggesting a more accurate representation of relaxin levels during pregnancy and parturition in mares.
Background of Study
- Equine relaxin (eRlx) is a hormone that plays a key role during pregnancy, specifically in the mare (female horse).
- Prior to this research, eRlx levels were measured using a porcine (pig) relaxin (pRlx) radioimmunoassay (RIA) – a test to measure the concentration of antibodies in the blood.
- This method was not optimal for measuring eRlx as the dose-response curve, which shows the effect of different doses on the outcome, was not parallel to the standard curve of pRlx.
Methodology
- To create a more accurate test, the researchers developed a homologous eRlx RIA. The term ‘homologous’ here means that the test was designed specifically for equine relaxin.
- This involved using highly purified eRlx to generate an antiserum (blood serum containing antibodies), prepare a tracer and establish assay standards.
- The team then tested this new eRlx-RIA and found it to be highly specific and sensitive, with a dose-response curve for eRlx plasma that was parallel to the equine standard curve, indicating a better fit for measuring eRlx.
Results
- The newly developed eRlx-RIA was then used to measure eRlx in samples collected during pregnancy that had previously been measured using the pRlx-RIA.
- Findings showed that the two assays produced almost identical patterns of secretion throughout pregnancy, but the eRlx-RIA measured higher amounts of relaxin during gestation than the pRlx assay.
- In instances of oxytocin-induced foalings, the disparity was more notable with the equine assay measuring up to 10 times greater concentrations.
- This confirms that the eRlx-RIA provides a more accurate representation of relaxin levels during pregnancy and parturition in mares.
Cite This Article
APA
Stewart DR.
(1986).
Development of a homologous equine relaxin radioimmunoassay.
Endocrinology, 119(3), 1100-1104.
https://doi.org/10.1210/endo-119-3-1100 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Female
- Horses
- Labor, Induced / veterinary
- Oxytocin / pharmacology
- Pregnancy
- Radioimmunoassay / methods
- Relaxin / analysis
Grant Funding
- HD-06386 / NICHD NIH HHS
Citations
This article has been cited 1 times.- Stewart DR, Henzel WJ, Vandlen R. Purification and sequence determination of canine relaxin. J Protein Chem 1992 Jun;11(3):247-53.
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