Development of homologous radioimmunoassays for equine growth hormone and equine prolactin and their application to the detection of circulating levels of hormone in horse plasma.
Abstract: Highly purified and well-characterised preparations of equine prolactin and growth hormone from equine pituitary glands were employed to set up highly sensitive and specific homologous radioimmunoassays (RIA) for the measurement of hormone in horse plasma. The limit of sensitivity of the GH RIA was 1.2 ng/ml with mean intra- and inter-assay coefficients of variation (CV) of 6.6 and 10%, respectively. The sensitivity of the equine prolactin (ePRL) RIA was 0.5 ng/ml with mean intra and inter-assay CV of 9.1 and 15.6%, respectively. Dose-response curves of a crude pituitary gland extract and plasma samples collected from a mare and foal were parallel to the standards and the PRL RIA was clinically validated by administration of thyrotropin-releasing hormone (TRH). Plasma samples taken at 15 min intervals over 24 h from lactating mares gave 24 h mean GH values in the range 5.5 to 7.95 ng/ml. Large intermittent elevations of GH activity were detected. The mean 24 h PRL concentrations were between 3.2-10.4 ng/ml in the lactating animals, with higher concentrations earlier in lactation. Long episodic bursts of PRL were detected.
Publication Date: 1994-01-01 PubMed ID: 7986349DOI: 10.1051/rnd:19940404Google Scholar: Lookup
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Summary
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The research paper presents an examination of the development of radioimmunoassays for horse growth hormone and equine prolactin and their efficacy in detecting these hormones in horse plasma.
Development of Radioimmunoassays
- The research involved utilising highly purified and well-characterised preparations of equine prolactin and growth hormone from equine pituitary glands.
- The researchers developed highly sensitive and specific homologous radioimmunoassays (RIA) for the measurement of these hormones in horse plasma.
- The equine growth hormone (GH) RIA had a sensitivity limit of 1.2 ng/ml with mean intra- and inter-assay coefficients of variation (CV) of 6.6 and 10%, respectively.
- The equine prolactin (ePRL) RIA showed a sensitivity of 0.5 ng/ml with mean intra and inter-assay CV of 9.1 and 15.6%, respectively, indicating a high degree of reproducibility and precision.
Application and Validation
- The dose-response curves of a crude pituitary gland extract and plasma samples from a mare and foal were found to be parallel to the standards, confirming the reliability of the assays.
- The prolactin RIA was clinically validated by the administration of thyrotropin-releasing hormone (TRH), a hormone that stimulates the pituitary gland to release prolactin and thyroid-stimulating hormone.
Measurement of Hormones in Horse Plasma
- Plasma samples were taken every 15 minutes over 24 hours from lactating mares.
- The mean 24-hour GH values ranged between 5.5 to 7.95 ng/ml. There were large, intermittent spikes in GH activity detected during this period.
- Similarly, the mean 24-hour prolactin concentrations in the lactating horses were between 3.2-10.4 ng/ml, with higher concentrations detected earlier during the lactation period.
- Long, episodic bursts of prolactin were observed.
Conclusion
- This research contributes to the knowledge of equine endocrinology and provides a reliable method for the measurement of equine growth hormone and prolactin in horse plasma.
Cite This Article
APA
Cahill CM, Van der Kolk H, Goode JA, Hayden TJ.
(1994).
Development of homologous radioimmunoassays for equine growth hormone and equine prolactin and their application to the detection of circulating levels of hormone in horse plasma.
Reprod Nutr Dev, 34(4), 309-328.
https://doi.org/10.1051/rnd:19940404 Publication
Researcher Affiliations
- Department of Zoology, University College Dublin, Belfield, Ireland.
MeSH Terms
- Animals
- Biological Assay
- Columbidae
- Dwarfism, Pituitary
- Fasting
- Female
- Growth Hormone / blood
- Growth Hormone / isolation & purification
- Growth Hormone-Releasing Hormone / pharmacology
- Guinea Pigs
- Horses / blood
- Lactation / physiology
- Mammary Glands, Animal / drug effects
- Mice
- Mice, Mutant Strains
- Peptide Fragments / pharmacology
- Pituitary Gland, Anterior / chemistry
- Prolactin / blood
- Prolactin / isolation & purification
- Rabbits
- Radioimmunoassay / methods
- Reference Standards
- Reproducibility of Results
- Secretory Rate / drug effects
- Sensitivity and Specificity
- Stomach, Avian / drug effects
- Thyrotropin-Releasing Hormone / pharmacology
Citations
This article has been cited 1 times.- Utama FE, Tran TH, Ryder A, LeBaron MJ, Parlow AF, Rui H. Insensitivity of human prolactin receptors to nonhuman prolactins: relevance for experimental modeling of prolactin receptor-expressing human cells.. Endocrinology 2009 Apr;150(4):1782-90.
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