EGF receptor-binding activity in the urine of normal horses and horses affected by chronic laminitis.
Abstract: A heterologous radioreceptor binding assay (RRA) has been developed capable of detecting nanogram amounts of epidermal growth factor (EGF) receptor-binding activity in equine urine. The binding parameters of [125I]mEGF (murine EGF) to EGF receptors on equine plasma membranes are in good agreement with values from other EGF-RRA systems. The dissociation constant estimated from equilibrium methods (KD = 4 X 10(-10) M) is in reasonable agreement with that determined from the rate constants (KD = 6 X 10(-10) M) and is in good agreement with values determined in other species. The assay is specific for equine EGF (eEGF) receptor-binding activity and capable of detecting less than 0.34 nM eEGF receptor-binding activity in urine. Equine EGF receptor-binding activity in equine urine form adult horses varied widely between samples (8.5 +/- 6.5 nM). This variability was somewhat reduced when values were adjusted for dilutional effects using urine creatinine as an indicator (3.6 +/- 2.0 nanomoles/g creatinine). No significant differences were demonstrated between the means of EGF binding activity concentrations in clinically normal horses and horses affected by chronic laminitis.
Publication Date: 1990-07-01 PubMed ID: 2390863DOI: 10.1016/0739-7240(90)90034-wGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The researchers developed a test that can detect extremely small amounts of a growth factor, which binds to certain receptors, in horse urine. They found that it works well, is specific, and can identify less than 0.34 nanomoles of this growth factor. They also discovered a lot of variability in results from horse to horse, although this lessened when they adjusted for the degree of urine dilution. When compared, there was no notable difference in these levels in healthy horses and horses with chronic laminitis.
Development of Radioreceptor Binding Assay (RRA)
- The researchers developed a heterologous radioreceptor binding assay (RRA) which has the capability to detect extremely small, nanogram level amounts of epidermal growth factor (EGF) receptor-binding activity in horse urine.
- The EGF receptor-binding activity is identified using a substance called murine EGF ([125I]mEGF), which binds with EGF receptors on horse plasma membranes.
- The strength of this binding was found to be in accordance with values from other similar EGF-RRA systems, confirming the effectiveness of the assay.
Dissociation constant of the RRA
- The dissociation constant (KD), which indicates the strength of bond between the two bound elements, was estimated to be in the vicinity of 4 X 10(-10) M to 6 X 10(-10) M.
- This KD value agrees with those in other species, further affirming the accuracy of the assay.
Specificity and Efficiency of the RRA
- The test is specifically designed for identifying the equine EGF (eEGF) receptor-binding activity and can detect amounts less than 0.34 nM.
EGF Receptor-Binding Activity in Horse Urine
- When measured in horse urine, EGF receptor-binding activity levels varied widely across samples (8.5 +/- 6.5 nM).
- To account for varying degrees of urine dilution across samples, the researchers adjusted the values using urine creatinine as an indicator, which led to reduced variability (3.6 +/- 2.0 nanomoles/g creatinine).
Comparison with Chronic Laminitis Affected Horses
- When comparing the average EGF binding activity concentrations in clinically normal horses with horses affected by chronic laminitis, no significant differences were found.
- This suggests that the presence of chronic laminitis does not notably affect EGF receptor-binding activity in horse urine.
Cite This Article
APA
Grosenbaugh DA, Amoss MS, Hood DM, Williams JD.
(1990).
EGF receptor-binding activity in the urine of normal horses and horses affected by chronic laminitis.
Domest Anim Endocrinol, 7(3), 277-289.
https://doi.org/10.1016/0739-7240(90)90034-w Publication
Researcher Affiliations
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Texas A&M University, College Station 77843.
MeSH Terms
- Animals
- Binding, Competitive
- Chromatography, High Pressure Liquid
- Chronic Disease
- Creatinine / urine
- Cross Reactions
- Epidermal Growth Factor / metabolism
- ErbB Receptors / metabolism
- ErbB Receptors / urine
- Foot Diseases / urine
- Foot Diseases / veterinary
- Hoof and Claw
- Horse Diseases / urine
- Horses
- Predictive Value of Tests
- Radioligand Assay
Citations
This article has been cited 1 times.- de Laat MA, Spence RJ, Sillence MN, Pollitt CC. An investigation of the equine epidermal growth factor system during hyperinsulinemic laminitis.. PLoS One 2019;14(12):e0225843.
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