Produção Nacional
VARIAÇÕES CÍCLICAS DO CORTISOL, TRIIODOTIRONINA (T3) E TIROXINA (T4) NO PERIPARTO DE ÉGUAS DA RAÇA QUARTO DE MILHA
2008; UNIVERSIDADE FEDERAL DE GOIÁS; Volume: 9; Issue: 2 Linguagem: Inglês
10.5216/cab.v9i2.539
ISSN1809-6891
AutoresPedrinho Paes Teixeira, Maria Lúcia Gambarini Meirinhos, João Teodoro Pádua, Dirson Vieira,
Tópico(s)Effects of Environmental Stressors on Livestock
ResumoThis study was designed to evaluate changes in plasma concentrations of cortisol (Cs), triiodothyronine (T3) and thyroxine (T4), as well as their circadian rhythm during peripartal period of Quarter Horse mares. Eighteen clinically healthy mares, with age between 60 and 96 months and alive weight (AW) between 350 and 420 Kg were divided in three groups (n=6) according the reproductive status, that means: no pregnant (TE), Pregnant (GE) and after parturition (PA).The blood samples were taken during 24 hours in intervals of two hours.There was no differences between cortisol levels regarding the reproductive status and periods of blood samples collections. This hormone showed a circadian rhythm, with accentuated oscillation in TE, but small for GE and PA. For T3 and T4 there was difference between reproductive status (P<0.05 and P<0.01), respectively, as well as for the periods (P<0.01 and P<0.05), respectively. It was possible to characterize the circadian rhythm for both hormones, verifying great oscillation for T3 in PA in the morning. It was possible to conclude that the final phase of pregnancy alter cortisol , T3 and T4 secretion standards, keeping, however, the rhythm, suggesting an organism adaptation along the peripartal period. KEY WORDS: Equine, reproductive status, hormones, circadian rhythm.
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