Analyze Diet
Journal of animal science2018; 96(1); 76-84; doi: 10.1093/jas/skx008

Free and bound cortisol in plasma and saliva during ACTH challenge in dairy cows and horses.

Abstract: Cortisol levels reflect hypothalamic-pituitary-adrenocortical (HPA) axis activity. While most plasma cortisol is supposed to be bound to the soluble corticosteroid-binding globulin (CBG), only free cortisol (FC) actively regulates metabolic and immunological processes. We aimed to establish a multispecies suitable method to assess FC in cows and horses which in combination with total cortisol (TC) allows interpreting proportional changes of cortisol in saliva as well as in blood in response to a standardized HPA axis activation via ACTH. We further investigated if the ratios of cortisol fractions as obtained at basal levels in healthy horses (herbivorous and monogastric) and dairy cows (herbivorous and ruminant) change during HPA axis activation, and to which extent saliva cortisol (SC) is representative for alterations in plasma FC and adrenal cortex reactivity. However, it was not the objective of the present study to directly compare the two species. Dosages of ACTH applied in cows and horses were based on published data. Synthetic ACTH was intravenously administered to eight dairy cows (0.16 µg/kg BW) and five horses (1 µg/kg BW). Blood and saliva were collected every 30 min for 3 h from a jugular vein catheter, and analyzed for TC and SC, the ratio of free cortisol (rFC), and the concentration of FC (cFC) in plasma. During the entire sampling period of the ACTH test, plasma TC was paralleled by blood cFC, rFC, and SC in both cows and horses. All cortisol fractions increased within 30 min of ACTH administration compared to basal values (0 min, P < 0.05). Peak TC concentration reached 63.2 ± 9.6 ng/mL and 73.2 ± 11.8 ng/mL in bovine and equine plasma, respectively. Peak values of rFC averaged 17.9 ± 4.5% in cows and 19.2 ± 7.8% in horses. The ratio of SC to cFC in horses remained similar during the ACTH challenge suggesting that SC is recruited from plasma FC. However, SC increased less compared to plasma TC and FC during HPA axis activation in cows. In conclusion, the short-term activation of the HPA axis caused not only an elevation of TC, but also a similar increase of rFC in both species. SC closely reflected changes of FC in horses, but less accurately in cows. The concomitant evaluation of changes among cortisol fractions might give further indications on adaptation mechanisms in glucocorticoid regulation as well as differentiate cortisol-related health disorders.
Publication Date: 2018-01-30 PubMed ID: 29378066PubMed Central: PMC6140936DOI: 10.1093/jas/skx008Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article investigates how cortisol levels in dairy cows and horses respond to a standardized activation of their hypothalamic-pituitary-adrenocortical (HPA) axis using synthetic Adrenocorticotropic Hormone (ACTH). It also explores the extent to which saliva cortisol is representative of alterations in plasma-free cortisol and adrenal cortex reactivity.

Objective of the Study

The goal of this study was to establish a method that can assess free cortisol (the form of cortisol that actively regulates metabolic and immunological processes) in cows and horses. This method allows interpretation of the proportional changes of cortisol in saliva and blood in response to a standardized HPA axis activation via synthetic ACTH. The researchers also aimed to determine if the ratios of cortisol fractions at basal levels in healthy horses and dairy cows change during HPA axis activation, and how reliable saliva cortisol (SC) is for presenting alterations in plasma-free cortisol (FC) and adrenal cortex reactivity.

Methodology

  • Synthetic ACTH was administered intravenously to eight dairy cows and five horses. The dosages were based on published data.
  • For 3 hours, blood and saliva were collected every 30 minutes from a jugular vein catheter. These samples were analyzed for total cortisol (TC) and SC, the ratio of free cortisol (rFC), and the concentration of FC in plasma.

Findings

  • All cortisol fractions increased within 30 minutes of ACTH administration compared to basal values (0 minutes).
  • Peak TC concentration reached 63.2 ± 9.6 ng/mL in bovine plasma and 73.2 ± 11.8 ng/mL in equine plasma.
  • Peak values of rFC averaged 17.9 ± 4.5% in cows and 19.2 ± 7.8% in horses.
  • The SC to cFC ratio in horses remained similar throughout the ACTH challenge, indicating that SC is sourced from plasma FC.
  • However, SC increased less compared to plasma TC and FC during HPA axis activation in cows.’

Conclusion

The research concluded that the short-term activation of the HPA axis through the administration of ACTH causes elevation of TC and a similar increase of rFC in both species. SC changes closely reflected FC changes in horses, but less accurately in cows. Understanding these changes among cortisol fractions could provide further insight into glucocorticoid regulation adaptation mechanisms and differentiate cortisol-related health disorders.

Cite This Article

APA
Schwinn AC, Sauer FJ, Gerber V, Bruckmaier RM, Gross JJ. (2018). Free and bound cortisol in plasma and saliva during ACTH challenge in dairy cows and horses. J Anim Sci, 96(1), 76-84. https://doi.org/10.1093/jas/skx008

Publication

ISSN: 1525-3163
NlmUniqueID: 8003002
Country: United States
Language: English
Volume: 96
Issue: 1
Pages: 76-84

Researcher Affiliations

Schwinn, Ann-Catherine
  • Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
  • Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
Sauer, Fay J
  • Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
  • Department of Clinical Veterinary Medicine, Swiss Institute for Equine Medicine (ISME), Vetsuisse Faculty, University of Bern, and Agroscope, Bern, Switzerland.
Gerber, Vincenz
  • Department of Clinical Veterinary Medicine, Swiss Institute for Equine Medicine (ISME), Vetsuisse Faculty, University of Bern, and Agroscope, Bern, Switzerland.
Bruckmaier, Rupert M
  • Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Gross, Josef J
  • Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.

MeSH Terms

  • Adaptation, Physiological
  • Administration, Intravenous / veterinary
  • Adrenocorticotropic Hormone / administration & dosage
  • Animals
  • Cattle / blood
  • Cattle / physiology
  • Dairying
  • Female
  • Glucocorticoids / metabolism
  • Hormones / administration & dosage
  • Horses / blood
  • Horses / physiology
  • Hydrocortisone / analysis
  • Hydrocortisone / blood
  • Hypothalamo-Hypophyseal System / physiology
  • Pituitary-Adrenal System / physiology
  • Saliva / chemistry
  • Specimen Handling / veterinary

References

This article includes 26 references
  1. Alexander SL, Irvine CH. The effect of social stress on adrenal axis activity in horses: the importance of monitoring corticosteroid-binding globulin capacity.. J Endocrinol 1998 Jun;157(3):425-32.
    pubmed: 9691975doi: 10.1677/joe.0.1570425google scholar: lookup
  2. Bartalena L, Hammond GL, Farsetti A, Flink IL, Robbins J. Interleukin-6 inhibits corticosteroid-binding globulin synthesis by human hepatoblastoma-derived (Hep G2) cells.. Endocrinology 1993 Jul;133(1):291-6.
    pubmed: 8391424doi: 10.1210/endo.133.1.8391424google scholar: lookup
  3. Bousquet-Mélou A, Formentini E, Picard-Hagen N, Delage L, Laroute V, Toutain PL. The adrenocorticotropin stimulation test: contribution of a physiologically based model developed in horse for its interpretation in different pathophysiological situations encountered in man.. Endocrinology 2006 Sep;147(9):4281-91.
    pubmed: 16763068doi: 10.1210/en.2005-1161google scholar: lookup
  4. Breuner CW, Delehanty B, Boonstra R. Evaluating stress in natural populations of vertebrates: total CORT is not good enough. Funct. Ecol. 2013;27:24–36.
    doi: 10.1111/1365-2435.12016google scholar: lookup
  5. Breuner CW, Orchinik M. Plasma binding proteins as mediators of corticosteroid action in vertebrates.. J Endocrinol 2002 Oct;175(1):99-112.
    pubmed: 12379494doi: 10.1677/joe.0.1750099google scholar: lookup
  6. Brossaud J, Gatta B, Tabarin A, Corcuff JB. Different methods to estimate serum free cortisol: a comparison during cortisol tetracosactide testing.. Clin Chem Lab Med 2015 Aug;53(9):1367-73.
    pubmed: 25381955doi: 10.1515/cclm-2014-0912google scholar: lookup
  7. Fureix C, Benhajali H, Henry S, Bruchet A, Prunier A, Ezzaouia M, Coste C, Hausberger M, Palme R, Jego P. Plasma cortisol and faecal cortisol metabolites concentrations in stereotypic and non-stereotypic horses: do stereotypic horses cope better with poor environmental conditions?. BMC Vet Res 2013 Jan 7;9:3.
    pmc: PMC3544618pubmed: 23289406doi: 10.1186/1746-6148-9-3google scholar: lookup
  8. Gayrard V, Alvinerie M, Toutain PL. Interspecies variations of corticosteroid-binding globulin parameters.. Domest Anim Endocrinol 1996 Jan;13(1):35-45.
    pubmed: 8625614doi: 10.1016/0739-7240(95)00042-9google scholar: lookup
  9. Gross JJ, Zbinden RS, Dohme-Meier F, Bruckmaier RM. Adrenal cortex reactivity in dairy cows differs between lactational stages and between different feeding levels.. J Anim Physiol Anim Nutr (Berl) 2018 Feb;102(1):e309-e315.
    pubmed: 28504317doi: 10.1111/jpn.12746google scholar: lookup
  10. Hammond GL, Smith CL, Paterson NA, Sibbald WJ. A role for corticosteroid-binding globulin in delivery of cortisol to activated neutrophils.. J Clin Endocrinol Metab 1990 Jul;71(1):34-9.
    pubmed: 2370299doi: 10.1210/jcem-71-1-34google scholar: lookup
  11. Hart KA, Barton MH, Ferguson DC, Berghaus R, Slovis NM, Heusner GL, Hurley DJ. Serum free cortisol fraction in healthy and septic neonatal foals.. J Vet Intern Med 2011 Mar-Apr;25(2):345-55.
  12. Hosoi K. Physiological role of aquaporin 5 in salivary glands.. Pflugers Arch 2016 Apr;468(4):519-39.
    pubmed: 26537593doi: 10.1007/s00424-015-1749-6google scholar: lookup
  13. Keremi B, Beck A, Fabian TK, Fabian G, Szabo G, Nagy A, Varga G. Stress and Salivary Glands.. Curr Pharm Des 2017 Oct 30;23(27):4057-4065.
  14. Levine A, Zagoory-Sharon O, Feldman R, Lewis JG, Weller A. Measuring cortisol in human psychobiological studies.. Physiol Behav 2007 Jan 30;90(1):43-53.
    pubmed: 17055006doi: 10.1016/j.physbeh.2006.08.025google scholar: lookup
  15. Lewis JG, Lewis MG, Elder PA. An enzyme-linked immunosorbent assay for corticosteroid-binding globulin using monoclonal and polyclonal antibodies: decline in CBG following synthetic ACTH.. Clin Chim Acta 2003 Feb;328(1-2):121-8.
    pubmed: 12559607doi: 10.1016/s0009-8981(02)00417-5google scholar: lookup
  16. Otovic P, Hutchinson E. Limits to using HPA axis activity as an indication of animal welfare.. ALTEX 2015;32(1):41-50.
    pubmed: 25418851doi: 10.14573/altex.1406161google scholar: lookup
  17. Peeters M, Sulon J, Beckers JF, Ledoux D, Vandenheede M. Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge.. Equine Vet J 2011 Jul;43(4):487-93.
  18. Proctor GB. The physiology of salivary secretion.. Periodontol 2000 2016 Feb;70(1):11-25.
    pubmed: 26662479doi: 10.1111/prd.12116google scholar: lookup
  19. Scheidegger MD, Gerber V, Bruckmaier RM, van der Kolk JH, Burger D, Ramseyer A. Increased adrenocortical response to adrenocorticotropic hormone (ACTH) in sport horses with equine glandular gastric disease (EGGD).. Vet J 2017 Oct;228:7-12.
    pubmed: 29153110doi: 10.1016/j.tvjl.2017.09.002google scholar: lookup
  20. Scheidegger MD, Gerber V, Ramseyer A, Schüpbach-Regula G, Bruckmaier RM, van der Kolk JH. Repeatability of the ACTH stimulation test as reflected by salivary cortisol response in healthy horses.. Domest Anim Endocrinol 2016 Oct;57:43-7.
  21. Schwinn AC, Knight CH, Bruckmaier RM, Gross JJ. Suitability of saliva cortisol as a biomarker for hypothalamic-pituitary-adrenal axis activation assessment, effects of feeding actions, and immunostimulatory challenges in dairy cows.. J Anim Sci 2016 Jun;94(6):2357-65.
    pubmed: 27285912doi: 10.2527/jas.2015-0260google scholar: lookup
  22. van der Kolk JH, Fouché N, Gross JJ, Gerber V, Bruckmaier RM. A comparison between the equine and bovine hypothalamus-pituitary-adrenocortical axis.. Domest Anim Endocrinol 2016 Jul;56 Suppl:S101-11.
  23. Verkerk GA, Macmillan KL, McLeay LM. Adrenal cortex response to adrenocorticotropic hormone in dairy cattle.. Domest Anim Endocrinol 1994 Jan;11(1):115-23.
    pubmed: 8124927doi: 10.1016/0739-7240(94)90039-6google scholar: lookup
  24. Vining RF, McGinley RA. The measurement of hormones in saliva: possibilities and pitfalls.. J Steroid Biochem 1987;27(1-3):81-94.
    pubmed: 3320544doi: 10.1016/0022-4731(87)90297-4google scholar: lookup
  25. Vining RF, McGinley RA, Maksvytis JJ, Ho KY. Salivary cortisol: a better measure of adrenal cortical function than serum cortisol.. Ann Clin Biochem 1983 Nov;20 (Pt 6):329-35.
    pubmed: 6316831doi: 10.1177/000456328302000601google scholar: lookup
  26. Yoshida C, Nakao T. Response of plasma cortisol and progesterone after ACTH challenge in ovariectomized lactating dairy cows.. J Reprod Dev 2005 Feb;51(1):99-107.
    pubmed: 15750301doi: 10.1262/jrd.51.99google scholar: lookup

Citations

This article has been cited 7 times.
  1. Nickles KR, Relling AE, Garcia-Guerra A, Fluharty FL, Parker AJ. Environmental stress during the last trimester of gestation in pregnant cows and its effect on offspring growth performance and response to glucose and adrenocorticotropic hormone. J Anim Sci 2023 Jan 3;101.
    doi: 10.1093/jas/skac332pubmed: 36592758google scholar: lookup
  2. Pinto G, Militello R, Amoresano A, Modesti PA, Modesti A, Luti S. Relationships between Sex and Adaptation to Physical Exercise in Young Athletes: A Pilot Study. Healthcare (Basel) 2022 Feb 11;10(2).
    doi: 10.3390/healthcare10020358pubmed: 35206972google scholar: lookup
  3. Contreras-Aguilar MD, Henry S, Coste C, Tecles F, Escribano D, Cerón JJ, Hausberger M. Changes in Saliva Analytes Correlate with Horses' Behavioural Reactions to An Acute Stressor: A Pilot Study. Animals (Basel) 2019 Nov 18;9(11).
    doi: 10.3390/ani9110993pubmed: 31752194google scholar: lookup
  4. Chen S, Wang J, Peng D, Li G, Chen J, Gu X. Exposure to heat-stress environment affects the physiology, circulation levels of cytokines, and microbiome in dairy cows. Sci Rep 2018 Oct 2;8(1):14606.
    doi: 10.1038/s41598-018-32886-1pubmed: 30279428google scholar: lookup
  5. Rachidi F, Wagner R, Fieseler H, Kaiser M, Müller H, Bittner-Schwerda L, Podpečan O, Mielenz N, Gottschalk J, Einspanier A, Möbius G, Starke A. Tears and saliva as alternative matrices for minimally invasive assessment of acute stress and pain in sheep. Front Vet Sci 2026;13:1719442.
    doi: 10.3389/fvets.2026.1719442pubmed: 41684387google scholar: lookup
  6. Briggs RK, Legako JF, Broadway PR, Carroll JA, Burdick Sanchez NC, Ineck NE, Smith ZK, Ramanathan R, Thornton KJ. Effects of Premortem Stress on Protein Expression, Steak Color, Oxidation, and Myofibrillar Fragmentation Index in the Longissimus Lumborum. Animals (Basel) 2024 Jul 25;14(15).
    doi: 10.3390/ani14152170pubmed: 39123696google scholar: lookup
  7. Kern J, Jorgensen MW, Boerman JP, Erasmus M, Johnson JS, Pempek JA. Effect of repeated HPA axis stimulation on hair cortisol concentration, growth, and behavior in preweaned dairy cattle. J Anim Sci 2024 Jan 3;102.
    doi: 10.1093/jas/skae171pubmed: 38898575google scholar: lookup