Thyroxine concentrations are elevated in mares which continue to exhibit estrous cycles during the nonbreeding season

Fitzgerald, B. P.; Davison, Laurie A.

doi:10.1016/s0737-0806(98)80186-x

Cited by 13 publications

(4 citation statements)

References 9 publications

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“…In a recent attempt thyroidectomy failed to alter the onset of anoestrus (Porter et al, 1995) which is similar to a previous observation on reproductive activity of thyroid-ectomized mares (Lowe et al, 1987). In contrast, using another approach, significant difference in plasma T 4 levels was found between cyclic and anestrous mares during the anovulatory season (Fitzgerald and Davison, 1998). In one of our studies (Huszenicza et al, 2000) we could detect certain relationships between thyroid function and expression of seasonal reproductive activity also in mares, but these results do not provide indisputable evidence for the involvement of the thyroid gland in the control of seasonality.…”

Section: Yroid Hormonal Regulation Of Seasonal Patterns Of Reproductioncontrasting

confidence: 73%

Clinical endocrinology of thyroid gland function in ruminants

Huszenicza¹,

Kulcsár²,

Rudas³

2002

Vet. Med.

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After briefly introducing the basec steps in production and metabolism of thyroid hormones, the author gives an overview of nutritional, metabolic and disease related factors and endocrine interactions influencing thyroid gland function in ruminants, particularly in the postpartum dairy cow. Involvement of thyroid hormonal regulation of seasonal patterns of reproduction as well as ovarian endocrine function are discussed.Keywords: thyroxin; triiodothyronine; ovary; metabolism; ruminants Abbreviations: 5'D = 5'-deiodinase (syn.: outer-ring deiodinase); 5D = 5-deiodinase (syn.: inner-ring deiodinase); BHB = βOH-butyrate; E 2 = 17β-estradiol; FSH = follicle stimulating hormone; GH = growth hormone; GnRH = gonadotropin releasing hormone; hCG = human chorionic gonadotropin; IGF-I = insulin-like growth factor-I (syn.: somatomedin C); IL = interleukin; LH = luteinizing hormone; mRNA = messenger ribonucleic acid; NEB = negative energy balance; NEFA = non-esterified fatty acids; P 4 = progesterone; PVN = paraventricular nucleus of the hypothalamus; rT 3 = 3,3',5'-triiodothyronine (syn.: reverse-triiodothyronine); T 3 = 3,3',5-triiodothyronine; T 4 = thyroxine; TNFα = tumor necrosis factor-α; TRH = thyrotropin-releasing hormone; TSH = thyroid-stimulating hormone (syn.: thyrotropin)

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Section: Yroid Hormonal Regulation Of Seasonal Patterns Of Reproductioncontrasting

confidence: 73%

Clinical endocrinology of thyroid gland function in ruminants

Huszenicza¹,

Kulcsár²,

Rudas³

2002

Vet. Med.

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“…A relationship between thyroid function and seasonal reproductive activity was investigated in mares (Huszenicza et al 2000) and significant differences in plasma thyroxine concentrations were observed between cyclic and anoestrous mares during anovulatory season (Fitzgerald and Davison 1998).…”

mentioning

confidence: 99%

Total and free iodothyronines profile in the donkey (Equus asinus) over a 12-month period

et al. 2012

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Several studies show the correlation between thyroid function and reproductive activity in horses, but no data are available in donkeys. The aim of this study was to determine physiological thyroid changes occurring in 10 pregnant and 14 barren donkeys over a period of 12 months. Blood samples were collected monthly from the jugular vein of pregnant and barren donkeys from June 2008 to June 2009. No significant differences (P < 0.05) in iodothyronine concentrations were observed between pregnant and barren donkeys in the same month. Seasonal total thyroxine (T 4 ) and free triiodothyronine (fT 3 ) patterns remained unmodified, regardless of physiological state, with the lowest T 4 levels at September and the highest at February, and the lowest fT 3 levels at June and the highest at July, in both pregnant and barren donkeys. Ranges of total triiodothyronine (T 3 ) concentrations in pregnant donkeys over a 12 months period ranged from 1.57 to 2

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“…Las THs se encargan de regular dinámicamente la polimerización de actina en astrocitos por un proceso no genómico, pues poseen la capacidad de organizar la actina en el citoesqueleto y desarrollar el cerebelo rápidamente una vez que se logra regular la migración neuronal (Fitzgerald, Davison, 1998). Además de las THs el yodo también cumple una función importante a nivel del tejido ovárico, ya que este tejido ovárico no sintetiza yodo proteínas hormonales, por ende su actividad de tomar y almacenar yodo puede ser inhibida por fármacos como el tiocianato, perclorato y dosis excesivas de yodo, situación que es conocida como el efecto Wolff-Chaikoff, lo cual también ocurre en el tejido tiroideo (Slebodzi´nski, 2005).…”

Section: Funciones De Las Hormonas Tiroideas En Los Equinosunclassified

Funcionamiento Normal Y Aumentado De La Glándula Tiroides en Equinos

Osório

Echeverry

2012

luaz

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Recibido el 10 de abril de 2012 y aprobado el 22 de agosto de 2012 RESUMEN Objetivo: Describir y analizar el funcionamiento normal de la glándula tiroides en equinos y los factores que aumentan en ellos los niveles de hormonas tiroideas. Materiales y métodos: Mediante la revisión de la literatura disponible de los últimos 50 años en las bases de datos BBCS-LILACS, fuente académica, IB-PsycINFO, IB-SSCI, IB-SciELO, Scopus y Scirus, al igual que artículos históricos, textos y referencias citadas en trabajos publicados. Resultados: la información obtenida relacionada con los objetivos propuestos en la presente revisión, permite clasificar en 4 secciones a saber: síntesis y secreción de hormonas tiroideas; transporte y metabolismo; funciones; hipertiroidismo en los equinos. Conclusión: La glándula tiroides juega un papel importante, como productora de hormonas tiroideas, las cuales son necesarias para la diferenciación celular y crecimiento del organismo. El buen funcionamiento de las vías metabólicas depende de estas hormonas, las que tienen efectos específicos sobre diferentes órganos, manteniendo la homeostasis en todos los tejidos. PALABRAS CLAVE Equinos, hormona tiroidea, metabolismo.

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Thyroxine concentrations are elevated in mares which continue to exhibit estrous cycles during the nonbreeding season

Cited by 13 publications

References 9 publications

Clinical endocrinology of thyroid gland function in ruminants

Clinical endocrinology of thyroid gland function in ruminants

Total and free iodothyronines profile in the donkey (Equus asinus) over a 12-month period

Funcionamiento Normal Y Aumentado De La Glándula Tiroides en Equinos

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