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Home / Equine Research Bank / J Anim Sci / Age and breed differences in thyroid hormones, insulin-like ...
Journal of animal science1996; 74(8); 1936-1942; doi: 10.2527/1996.7481936x

Age and breed differences in thyroid hormones, insulin-like growth factor (IGF)-I and IGF binding proteins in female horses.

Abstract: A survey with horses was conducted to determine whether plasma concentrations of triiodothyronine (T3), thyroxine (T4), insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) change as horses grow, mature sexually, and age. Jugular blood was sampled from Standardbred fillies and mares at ages 0, 1, 7, and 14 d, at 1, 2, 4, 5, 6, and 9 mo, and at 5 to 8 and 16 to 22 yr (n = 5 to 18). In a second survey, we measured the same variables in eight breeds of horses with markedly different adult body sizes, from Miniatures to Friesians. Plasma T3, T4, and IGF-I were determined by radioimmunoassays validated for horses, and IGFBP were estimated from radioligand assay following separation of the IGFBP by SDS-PAGE electrophoresis. Plasma T3 decreased (P < .01) nearly continuously from 7.9 ng/mL on the day of birth to .9 ng/mL at 6 mo, and then changed little from .7 ng/mL at 9 mo to .5 ng/mL in mares 16 to 22 yr old. Similarly, T4 declined (P < .01) from 233 ng/mL on the day of birth to 49 ng/mL at 14 d and varied from 35 to 9 ng/mL among all of the older age groups. Plasma concentrations of IGF-I increased (P < .01) from 285 ng/mL on the day of birth to 572 ng/mL at 14 d, remained relatively constant until 9 mo of age (530 ng/mL), and then declined (P < .01) to low levels (295 ng/mL) in the oldest mares. We detected six IGFBP. The two smallest IGFBP (26 and 39 kDa) were highest during the first 14 d after birth and lowest (P .20). In agreement with data for other species, our data suggest that IGF-I and IGFBP modulate growth in horses. Although there were impressive interbreed differences in circulating concentrations of T3, T4, IGF-I, and IGFBP, these were not related to differences in adult body size.
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Publication Date: 1996-08-01 PubMed ID: 8856448DOI: 10.2527/1996.7481936xGoogle Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't
  • Research Support
  • U.S. Gov't
  • Non-P.H.S.

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.

This study examines the variances in plasma levels of thyroid hormones, insulin-like growth factor (IGF)-I and IGF binding proteins in female horses as they age and mature. The research discovered significant variations, which however, did not directly correlate with adult body size.

Methodology

  • The study was conducted through two surveys. One involving Standardbred fillies and mares at different ages from birth to 22 years. The second survey involved horses from eight different breeds. Samples were collected from horses of markedly different adult body sizes, from Miniatures to Friesians.
  • Jugular blood was sampled and the plasma concentrations of triiodothyronine (T3), thyroxine (T4), insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) were evaluated.
  • Identification and measurement of plasma T3, T4, and IGF-I was carried out using radioimmunoassays validated for horses. IGFBP were evaluated from radioligand assay after separating the IGFBP by SDS-PAGE electrophoresis.

Findings

  • Plasma T3 decreased consistently from 7.9 ng/mL on the day of birth to 0.5 ng/mL in mares 16 to 22 years old.
  • Plasma T4 similarly fell from 233 ng/mL on the day of birth to 49 ng/mL at 14 days. It varied from 35 to 9 ng/mL in all adult age groups.
  • Plasma concentrations of IGF-I rose from 285 ng/mL on the day of birth to 572 ng/mL at 14 days, maintained this level until 9 months of age (530 ng/mL), and then declined (P < .01) to low levels (295 ng/mL) in the oldest mares.
  • Six IGFBP were detected. The two smallest IGFBP (26 and 39 kDa) were highest during the first 14 days after birth and lowest in aged mares. The four larger IGFBP had their lowest values at birth and increased to the highest levels during the most rapid growth phase, though these changes were not significant.

Conclusion

  • Numerous changes were observed in plasma T3, T4, IGF-I, and IGFBP concentrations as the horses grew, matured sexually, and aged.
  • While there were noticeable differences between breeds in circulating concentrations of these hormones and proteins, these variances did not necessarily represent their differences in adult body size.
  • This study provides evidence that IGF-I and IGFBP are important factors modulating growth in horses, consistent with data from other species.

Cite This Article

APA
Malinowski K, Christensen RA, Hafs HD, Scanes CG. (1996). Age and breed differences in thyroid hormones, insulin-like growth factor (IGF)-I and IGF binding proteins in female horses. J Anim Sci, 74(8), 1936-1942. https://doi.org/10.2527/1996.7481936x

Publication

Journal of animal science
ISSN: 0021-8812
NlmUniqueID: 8003002
Country: United States
Language: English
Volume: 74
Issue: 8
Pages: 1936-1942

Researcher Affiliations

Malinowski, K
  • Department of Animal Science, Rutgers, State University of New Jersey, New Brunswick 08903, USA.
Christensen, R A
    Hafs, H D
      Scanes, C G

        MeSH Terms

        • Aging / blood
        • Animals
        • Autoradiography / veterinary
        • Blotting, Western / veterinary
        • Body Constitution / physiology
        • Breeding
        • Electrophoresis, Polyacrylamide Gel / veterinary
        • Female
        • Horses / blood
        • Horses / genetics
        • Horses / physiology
        • Insulin-Like Growth Factor Binding Proteins / blood
        • Insulin-Like Growth Factor I / analysis
        • Thyroxine / blood
        • Triiodothyronine / blood

        Citations

        This article has been cited 8 times.
        1. Merkies K, Paraschou G, McGreevy PD. Morphometric Characteristics of the Skull in Horses and Donkeys-A Pilot Study. Animals (Basel) 2020 Jun 8;10(6).
          doi: 10.3390/ani10061002pubmed: 32521777google scholar: lookup
        2. Robeck TR, Amaral RS, da Silva VMF, Martin AR, Montano GA, Brown JL. Thyroid hormone concentrations associated with age, sex, reproductive status and apparent reproductive failure in the Amazon river dolphin (Inia geoffrensis). Conserv Physiol 2019;7(1):coz041.
          doi: 10.1093/conphys/coz041pubmed: 31384468google scholar: lookup
        3. Robles M, Nouveau E, Gautier C, Mendoza L, Dubois C, Dahirel M, Lagofun B, Aubrière MC, Lejeune JP, Caudron I, Guenon I, Viguié C, Wimel L, Bouraima-Lelong H, Serteyn D, Couturier-Tarrade A, Chavatte-Palmer P. Maternal obesity increases insulin resistance, low-grade inflammation and osteochondrosis lesions in foals and yearlings until 18 months of age. PLoS One 2018;13(1):e0190309.
          doi: 10.1371/journal.pone.0190309pubmed: 29373573google scholar: lookup
        4. Mochizuki M, Hayakawa N, Minowa F, Saito A, Ishioka K, Ueda F, Okubo K, Tazaki H. The concentration of iodine in horse serum and its relationship with thyroxin concentration by geological difference. Environ Monit Assess 2016 Apr;188(4):226.
          doi: 10.1007/s10661-016-5221-7pubmed: 26972926google scholar: lookup
        5. Peugnet P, Wimel L, Duchamp G, Sandersen C, Camous S, Guillaume D, Dahirel M, Dubois C, Jouneau L, Reigner F, Berthelot V, Chaffaux S, Tarrade A, Serteyn D, Chavatte-Palmer P. Enhanced or reduced fetal growth induced by embryo transfer into smaller or larger breeds alters post-natal growth and metabolism in pre-weaning horses. PLoS One 2014;9(7):e102044.
          doi: 10.1371/journal.pone.0102044pubmed: 25006665google scholar: lookup
        6. Verwilghen DR, Vanderheyden L, Franck T, Busoni V, Enzerink E, Gangl M, Lejeune JP, van Galen G, Grulke S, Serteyn D. Variations of plasmatic concentrations of Insulin-like Growth Factor-I in post-pubescent horses affected with developmental osteochondral lesions. Vet Res Commun 2009 Oct;33(7):701-9.
          doi: 10.1007/s11259-009-9219-2pubmed: 19319655google scholar: lookup
        7. Lejeune JP, Franck T, Gangl M, Schneider N, Michaux C, Deby-Dupont G, Serteyn D. Plasma concentration of insulin-like growth factor I (IGF-I) in growing Ardenner horses suffering from juvenile digital degenerative osteoarthropathy. Vet Res Commun 2007 Feb;31(2):185-95.
          doi: 10.1007/s11259-006-3385-2pubmed: 17216321google scholar: lookup
        8. Stoeckle SD, Stage HJ, Gehlen H. Thyroid Disease in Horses-Retrospective Case Series on Patients Examined for Thyroid Disease in an Equine University Clinic (2009-2024). Vet Sci 2025 Nov 27;12(12).
          doi: 10.3390/vetsci12121127pubmed: 41472107google scholar: lookup
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