Hypothalamic-pituitary-adrenal axis assessment in healthy term neonatal foals utilizing a paired low dose/high dose ACTH stimulation test.
Abstract: Hypothalamic-pituitary-adrenal (HPA) axis function is dynamic in the neonatal foal. The paired low dose/high dose cosyntropin (ACTH) stimulation test allows comprehensive HPA axis assessment, but has not been evaluated in neonatal foals. Objective: Foal age will significantly affect cortisol responses to a paired 10 and 100 microg dose cosyntropin stimulation test in healthy neonatal foals. Methods: Twenty healthy neonatal foals. Methods: HPA axis function was assessed in 12 foals at birth and at 12-24, 36-48 hours, and 5-7 days of age. At each age, basal cortisol and ACTH concentrations were measured and cortisol responses to 10 and 100 microg cosyntropin were assessed with a paired ACTH stimulation test protocol. Eight additional 36-48-hour-old foals received saline instead of 10 microg cosyntropin in the same-paired ACTH stimulation test design. Results: At birth, foals had significantly higher basal cortisol and ACTH concentrations and higher basal ACTH : cortisol ratios compared with foals in all other age groups. A significant cortisol response to both the 10 and 100 microg doses of cosyntropin was observed in all foals. The magnitude of the cortisol response to both doses of cosyntropin was significantly different across age groups, with the most marked responses in younger foals. There was no effect of the paired ACTH stimulation test design itself on cortisol responses. Conclusions: A paired 10 and 100 microg cosyntropin stimulation test can be used to evaluate HPA axis function in neonatal foals. Consideration of foal age is important in interpretation of HPA axis assessment.
Publication Date: 2008-02-03 PubMed ID: 19192152DOI: 10.1111/j.1939-1676.2008.00271.xGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
- Adrenocorticotropic Hormone (ACTH)
- Age Factors
- Animal Health
- Biochemistry
- Clinical Pathology
- Clinical Study
- Comparative Study
- Cortisol
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Endocrine System
- Equine Diseases
- Equine Health
- Foals
- Hormones
- Horses
- Hypothalamic Pituitary Adrenal Axis
- Physiology
- Veterinary Medicine
- Veterinary Research
Summary
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The research investigates the function of the Hypothalamic-pituitary-adrenal (HPA) axis in newborn horses using a paired low dose/high dose ACTH stimulation test. It reveals that the age of the foal significantly impacts its cortisol response to the test.
Research Overview
- The study aimed to provide a comprehensive assessment of the Hypothalamic-pituitary-adrenal (HPA) axis function in neonatal foals or young horses using a paired low dose/high dose ACTH (Adrenocorticotropic hormone) stimulation test. It hypothesized that a foal’s age significantly affects its cortisol responses to the test.
- The HPA axis is a critical communication system between the brain and the adrenal glands. It is key for the body’s response to stress by controlling the production of cortisol. In neonatal foals, the HPA axis function is dynamic and changes rapidly during their early life stages, and this study focused on understanding this change.
Methodology
- A total of 20 healthy foals were examined, with 12 of them assessed at birth and then at 12-24 hours, 36-48 hours, and 5-7 days of age.
- During this period, basal cortisol and ACTH concentrations were measured. The cortisol responses to 10 and 100 micrograms of cosyntropin, a synthetic ACTH, were tested using a paired ACTH stimulation test protocol.
- In addition to this, 8 other foals of 36-48-hours-old were administered saline instead of the 10 micrograms cosyntropin to control the testing process.
Results
- Foals at birth had considerably higher cortisol, ACTH concentrations and ACTH to cortisol ratios than those in all other age groups.
- All foals exhibited a significant cortisol response to both the 10 and 100 micrograms doses of cosyntropin.
- The reaction to both doses of cosyntropin varied across age groups, with more marked responses in younger foals.
- The paired ACTH stimulation test design itself did not impact the cortisol responses.
Conclusions
- The findings indicate that a paired 10 and 100 micrograms cosyntropin stimulation test can effectively investigate the HPA axis function in neonatal foals.
- The age of the foal plays a significant role in interpreting HPA axis assessment data, and hence is a significant factor to consider during the evaluation.
Cite This Article
APA
Hart KA, Heusner GL, Norton NA, Barton MH.
(2008).
Hypothalamic-pituitary-adrenal axis assessment in healthy term neonatal foals utilizing a paired low dose/high dose ACTH stimulation test.
J Vet Intern Med, 23(2), 344-351.
https://doi.org/10.1111/j.1939-1676.2008.00271.x Publication
Researcher Affiliations
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA. khart4@uga.edu
MeSH Terms
- Age Factors
- Animals
- Animals, Newborn
- Cosyntropin / administration & dosage
- Dose-Response Relationship, Drug
- Female
- Horses / blood
- Horses / physiology
- Hydrocortisone / blood
- Hypothalamo-Hypophyseal System / drug effects
- Hypothalamo-Hypophyseal System / physiology
- Male
- Pituitary-Adrenal System / drug effects
- Pituitary-Adrenal System / physiology
Citations
This article has been cited 7 times.- Elder E, Wong D, Johnson K, Robertson H, Marner M, Dembek K. Assessment of the hypothalamic-pituitary-adrenocortical axis function using a vasopressin stimulation test in neonatal foals.. J Vet Intern Med 2023 Sep-Oct;37(5):1881-1888.
- Boakari YL, Legacki E, Alonso MA, Dos Santos ACF, Nichi M, Conley AJ, Fernandes CB. Postnatal Dynamics of Circulating Steroid Hormones in Mule and Equine Neonates.. Vet Sci 2022 Oct 28;9(11).
- Kinsella HM, Hostnik LD, Rings LM, Swink JM, Burns TA, Toribio RE. Glucagon, insulin, adrenocorticotropic hormone, and cortisol in response to carbohydrates and fasting in healthy neonatal foals.. J Vet Intern Med 2021 Jan;35(1):550-559.
- Swink JM, Rings LM, Snyder HA, McAuley RC, Burns TA, Dembek KA, Gilsenan WF, Browne N, Toribio RE. Dynamics of androgens in healthy and hospitalized newborn foals.. J Vet Intern Med 2021 Jan;35(1):538-549.
- Aleman M, McCue PM, Chigerwe M, Madigan JE. Plasma concentrations of steroid precursors, steroids, neuroactive steroids, and neurosteroids in healthy neonatal foals from birth to 7 days of age.. J Vet Intern Med 2019 Sep;33(5):2286-2293.
- Hart KA, Barton MH, Vandenplas ML, Hurley DJ. Effects of low-dose hydrocortisone therapy on immune function in neonatal horses.. Pediatr Res 2011 Jul;70(1):72-7.
- Hart KA, Barton MH. Adrenocortical insufficiency in horses and foals.. Vet Clin North Am Equine Pract 2011 Apr;27(1):19-34.
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