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Relationship between circulating tri-iodothyronine and cortisol in the perinatal period in the foal.
Abstract: Pre- and post partum changes in plasma T3 have been examined in relation to plasma cortisol in 23 newborn foals (12 full term, 6 premature and 5 'twilight'), and in 5 fetuses catheterized in late gestation. Blood samples were collected daily from the fetuses and from the neonates at 30-min intervals for 2 h after birth; the plasma was assayed for T3 and cortisol by standard radioimmunoassay methods. In the full-term foals, plasma cortisol and T3 concentrations were high at birth (67.4 +/- 6.1 and 4.3 +/- 0.3 ng/ml respectively) and rose to a maximum during the following 2-h period to 141.0 +/- 8.8 ng/ml and 8.4 +/- 0.5 ng/ml. The corresponding changes in the premature foals over the same period were significantly lower (P less than 0.01; 17.2 +/- 2.2 to 27.0 +/- 4.3 ng cortisol/ml and 2.9 +/- 0.5 to 5.4 +/- 0.6 ng T3/ml). In the 'twilight' group, intermediate increases in both cortisol and T3 were observed. In the 5 chronically catheterized fetuses, both plasma cortisol and T3 were low in the last few weeks of gestation (7.0 +/- 1.1 ng/ml and 1.2 +/- 0.2 ng/ml respectively). In 2 fetuses there was little or no increase in plasma cortisol or T3 before induction of labour at about 320 days; one foal was premature and the other 'twilight'. Infusion of adrenocorticotrophic hormone for 4.5 days into the third fetus from 309 days led to an increase in both cortisol and T3 and the birth of a viable, full term foal. The 2 remaining fetuses were delivered spontaneously, one at term and one at 300 days (well before term). The latter was viable but dysmature; it showed a slight prenatal rise in plasma cortisol with little change in T3. When all the data were combined from both fetuses and neonates a significant positive correlation between plasma T3 and cortisol was found (P less than 0.001). These results demonstrate a relationship between circulating cortisol and T3 in the perinatal period and show that prematurity is associated with low concentrations of both hormones.
Publication Date: 1991-01-01 PubMed ID: 1665521 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
- Research Support
- Non-U.S. Gov't
Summary
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This research investigates the relationship between the hormones tri-iodothyronine (T3) and cortisol in the blood of newborn foals. The study finds that concentrations of these hormones vary depending on whether a foal is born at full term, prematurely, or ‘twilight’, and suggests that prematurity is linked with low levels of both hormones.
Methodology and Sampling
- The study was conducted on a total of 23 newborn foals, which included 12 full-term, 6 premature, and 5 ‘twilight’ foals, and 5 fetuses who were catheterized in their late gestation period.
- Blood samples were collected daily from the fetuses and from the neonates at 30-minute intervals for 2 hours after birth in order to measure the plasma T3 and cortisol levels using standard radioimmunoassay methods.
Results and Observations
- In full-term foals, the concentration of plasma cortisol and T3 were observed to be high at birth and rose to a maximum during the following 2-hour period.
- However, in premature foals, increases in cortisol and T3 levels over the same period were significantly lower.
- The ‘twilight’ group showed intermediate increases in both cortisol and T3 levels.
- In chronic catheterized fetuses, low levels of plasma cortisol and T3 were observed in the last few weeks of gestation.
- In some cases, there was little or no increase in plasma cortisol or T3 prior to induced labour.
- An infusion of adrenocorticotrophic hormone in one of the fetuses led to an increase in both cortisol and T3 levels and resulted in the birth of a viable, full-term foal.
- The study also noted cases where fetuses were delivered prematurely and were viable but dysmature, showing a slight prenatal rise in plasma cortisol with little change in T3.
Conclusions
- When the data from both fetuses and neonates were combined, a significant positive correlation between plasma T3 and cortisol was found.
- The results demonstrate a relationship between circulating cortisol and T3 in the perinatal period, indicating that these hormones may play an important role in fetal development and birth timing.
- It was also noted that prematurity is associated with low concentrations of both these hormones.
Cite This Article
APA
Silver M, Fowden AL, Knox J, Ousey J, Cash R, Rossdale PD.
(1991).
Relationship between circulating tri-iodothyronine and cortisol in the perinatal period in the foal.
J Reprod Fertil Suppl, 44, 619-626.
Publication
Researcher Affiliations
- Physiological Laboratory, Cambridge, U.K.
MeSH Terms
- Adrenocorticotropic Hormone / blood
- Animals
- Animals, Newborn / blood
- Fetal Blood / chemistry
- Horses / blood
- Hydrocortisone / blood
- Thyroxine / blood
- Triiodothyronine / blood
Grant Funding
- Wellcome Trust
Citations
This article has been cited 5 times.- Ishimaru M, Kume K, Murase H, Sato F, Matsui A, Ohmura H, Taya K. Effect of birth month on endocrine function in Thoroughbred foals born in Hokkaido, the northern part of Japan. J Vet Med Sci 2025 Jul 7;87(7):804-815.
- Lauteri E, Mariella J, Beccati F, Roelfsema E, Castagnetti C, Pepe M, Peric T, Barbato O, Montillo M, Rouge S, Freccero F. Adrenal Gland Ultrasonographic Measurements and Plasma Hormone Concentrations in Clinically Healthy Newborn Thoroughbred and Standardbred Foals. Animals (Basel) 2021 Jun 19;11(6).
- Müller V, Toribio RE, Dembek K, Moraes BSS, Mousquer MA, Curcio BR, Nogueira CEW. Serum cortisol and thyroid hormone concentrations and survival in foals born from mares with experimentally induced ascending placentitis. J Vet Intern Med 2020 May;34(3):1332-1338.
- 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.
- Breuhaus BA. Thyroid function and dysfunction in term and premature equine neonates. J Vet Intern Med 2014 Jul-Aug;28(4):1301-9.
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