The study was carried out to investigate the changes of circulating β-endorphin, adrenocorticotropic hormone (ACTH) and cortisol concentrations in 18 Thoroughbred mares (n=12 pregnant and n=6 barren), aged 5-18 years, over a 12–month period. Blood samples were collected monthly from April to March. In pregnant mares there were no significant changes in β-endorphin and ACTH levels (P>0.05), but higher cortisol levels at the 1st (P<0.05) and at the 8th (P<0.01) and lower at the 11th gestation month (P<0.01) were observed, as compared to barren mares. Pregnant mares showed higher β-endorphin levels in August (P<0.05), lower ACTH levels in July (P<0.05) and higher cortisol levels in May (P<0.05), as compared to the previous month. Barren mares showed lower cortisol levels in April (P<0.05) and in November (P<0.01) and higher levels in March (P<0.001), as compared to pregnant mares and in the 1st post-partum month values. Barren mares exhibited higher β-endorphin levels in September (P<0.05) and lower in November (P<0.01) and December (P<0.01), vs the previous month. One-way RM-ANOVA showed a seasonal effect for β-endorphin (P<0.001), ACTH (P<0.001) and cortisol (P<0.001) changes in pregnant mares, and for β-endorphin (P<0.0001) and cortisol (P<0.0001) changes in barren mares.
Seasonal patterns of circulating beta-endorphin, adrenocorticotropic hormone and cortisol levels in pregnant and barren mares
FAZIO, Esterina;MEDICA, Pietro;FERLAZZO, Adriana
2009-01-01
Abstract
The study was carried out to investigate the changes of circulating β-endorphin, adrenocorticotropic hormone (ACTH) and cortisol concentrations in 18 Thoroughbred mares (n=12 pregnant and n=6 barren), aged 5-18 years, over a 12–month period. Blood samples were collected monthly from April to March. In pregnant mares there were no significant changes in β-endorphin and ACTH levels (P>0.05), but higher cortisol levels at the 1st (P<0.05) and at the 8th (P<0.01) and lower at the 11th gestation month (P<0.01) were observed, as compared to barren mares. Pregnant mares showed higher β-endorphin levels in August (P<0.05), lower ACTH levels in July (P<0.05) and higher cortisol levels in May (P<0.05), as compared to the previous month. Barren mares showed lower cortisol levels in April (P<0.05) and in November (P<0.01) and higher levels in March (P<0.001), as compared to pregnant mares and in the 1st post-partum month values. Barren mares exhibited higher β-endorphin levels in September (P<0.05) and lower in November (P<0.01) and December (P<0.01), vs the previous month. One-way RM-ANOVA showed a seasonal effect for β-endorphin (P<0.001), ACTH (P<0.001) and cortisol (P<0.001) changes in pregnant mares, and for β-endorphin (P<0.0001) and cortisol (P<0.0001) changes in barren mares.Pubblicazioni consigliate
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