Thyroid Hormone Relationships in the Fetal and Newborn Lamb

Mathur, H. S.; Brown, Brian; Krane, Elliot J.; Thomas, Albert; Nathanielsz, P. W.

doi:10.1159/000241265

Cited by 15 publications

(10 citation statements)

References 7 publications

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“…The changes in plasma T3 and T4 levels are in agreement with the results of Nathaniels: [28], T3 increased sharply between birth and 8 h. as shown in other experiments [4,23,27,29]; since the thyroid of newborn infants or piglets contains few T, residues at this age [12], by analogy, the increase in the lamb is probably linked, as proposed earlier [23,27], with an activation of the 5'-iodothyronine deiodinasc enzyme which converts T4 to Tv After a decrease associated with a drop of the substrate T4 (the T3/T4 ratio remained un changed). the plasma Tj levels increased up to day 11; one part of this rise was related with the increase of T4 between 16 and 36 h (Tj/T4 unchanged): the other part occurred with a simultaneous decrease of T4; therefore, the value of the T3/T4 ratio increased sharply during this period (31-50 X 10-5).…”

Section: Neonatal Changes In the Plasma Cortisol T4 And Ts Levelssupporting

confidence: 91%

Hormonal Status in the Newborn Lamb (Cortisol, T3, T4)

Cabello¹,

Levieux²

1981

Neonatology

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The experiments reported involve 18 Romanov lambs born spontaneously between 135 and 145 days of gestation. Their birth weights ranged between 1.22 and 3.55 kg. The neonatal changes in plasma cortisol, triiodothyronine and thyroxine levels were observed from birth to 30 days postpartum, and related to the length of gestation and the birth weight. Positive correlations were found between: (1) plasma T₃ (2, 4, 8 h and 11 days after birth), T₄ levels (4 h after birth) and the birth weight; (2) plasma T₃ levels (2, 4 and 8 h after birth) and the weight gain during the 1st month of life, and (3) plasma cortisol levels at birth, 8 and 48 h postpartum and the litter size. Negative correlations were found between: (1) plasma cortisol levels (at birth, 2, 4, 8 and 48 h postpartum) and the birth weight; (2) plasma cortisol levels (2, 8 and 48 h after birth) and the length of gestation, and (3) values of the T₃/T₄ ratio and the litter size. A tentative scheme of the interactions between litter size, hormonal plasma levels, length of gestation and birth weight is proposed. Moreover, the effects of placental insufficiency and insufficient plasma levels of thyroid hormones could explain partly the high frequency of disease which occurs in low birth weight lambs.

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Section: Neonatal Changes In the Plasma Cortisol T4 And Ts Levelssupporting

confidence: 91%

Hormonal Status in the Newborn Lamb (Cortisol, T3, T4)

Cabello¹,

Levieux²

1981

Neonatology

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“…Up to date, few data have been published on neonatal changes in plasma reverse T3 levels in lambs. In the suckling animals, they progressively decreased from birth to 48 h post partum, in agreement with the partial data of Mathur et al (1980). Such a profile is detectable from Day 132 of gestation in the lamb foetus .…”

Section: Introductionsupporting

confidence: 88%

Plasma free and total iodothyronine levels in the newborn lamb. Physiological considerations

Cabello¹,

Wrutniak²

1986

Reprod. Nutr. Dévelop.

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“…In this study, as stated before, the higher serum concentration of T 3 on the day of parturition (1.77 ng/ml) when compared to the periods of lactation could be related to the glucocorticoid concentrations, which increase at the end of gestation (Chopra et al, 1975;Mathur et al, 1980). The glucocorticoids stimulate the hepatic and renal deiodination of T 4 and T 3 , which increases the serum concentration of T 3 and may decrease the concentration of T 4 (Thomas et al, 1978;Graf and Carvalho, 2002).…”

Section: Discussionsupporting

confidence: 67%

Serum concentration of thyroid hormones in crioula lanada serrana ewes in gestation and lactation

Colodel

Martins

et al. 2010

Arch. zootec.

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SUMMARYThe effects of gestation and lactation on the dynamics of the thyroid hormones, triiodothyronine (T 3 ) and thyroxine (T 4 ) were evaluated in Crioula Lanada Serrana ewes from the plateau region in Santa Catarina -Brazil. To evaluate the effects of gestation, twenty four ewes were randomly divided into groups I and II. Group I was composed of 12 pregnant ewes and the control group (II) was composed of 12 non-pregnant ewes. The effects of lactation were evaluated in the same ewes of group I after parturition (LE) and in the control group (NL). Blood samples were taken in the first, second and third periods of gestation, at parturition, and at 30, 60 and 90 days of lactation. T 3 and T 4 concentrations were determined by radioimmunoassay (RIA). Pregnant ewes showed lower serum concentrations of T 3 and T 4 than those of non-pregnant ewes. At parturition, there was no significant difference in T 3 concentrations between groups I and II (p>0.05). During lactation, serum T 3 concentrations were lower (p≤0.05) in LE than in NL ewes. Serum T 3 concentrations were greater (p≤0.05) at lambing than during the lactation periods. Serum T 4 concentrations in LE at parturition did not differ (p>0.05) from those of NL ewes. During lactation, T 4 concentrations of LE were lower (p≤0.05) than those of the NL ewes. The results of this study have shown that gestation causes a variation in the T 3 and T 4 serum concentrations, and that lactation results in a decrease of serum concentrations of T 3 and T 4 in Crioula Lanada Serrana ewes. RESUMOOs efeitos da gestação e lactação sobre a dinâmica dos hormônios tireoidianos triiodotironina (T 3 ) e tiroxina (T 4 ) foram avaliados em ovelhas Crioula Lanada Serrana na região do Planalto Serrano Catarinense. Para avaliar os efeitos da gestação, foram utilizadas vinte e quatro ovelhas distribuídas aleatoriamente em dois grupos. O grupo I foi formado por 12 ovelhas gestantes e o grupo controle por 12 ovelhas não gestantes (grupo II). Os efeitos da lactação foram avaliados nas mesmas ovelhas do grupo I após a parição (LE) e no grupo controle (NL). Foram colhidas amostras sanguíneas no primeiro, segundo e terceiro terço da gestação, ao parto e aos 30, 60 e 90 dias de lactação. As concentrações de T 3 e T 4 foram determinadas por radioimunoensaio (RIA). As ovelhas gestantes apresentaram concentrações séricas de T 3 e T 4 inferiores àquelas não gestantes. Ao parto não houve diferença significativa nas concentrações de T 3 entre os grupos I e II (p>0,05). Durante a lactação as concentrações Archivos de zootecnia vol. 59, núm. 228, p. 510

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Thyroid Hormone Relationships in the Fetal and Newborn Lamb

Cited by 15 publications

References 7 publications

Hormonal Status in the Newborn Lamb (Cortisol, T<sub>3</sub>, T<sub>4</sub>)

Hormonal Status in the Newborn Lamb (Cortisol, T<sub>3</sub>, T<sub>4</sub>)

Plasma free and total iodothyronine levels in the newborn lamb. Physiological considerations

Serum concentration of thyroid hormones in crioula lanada serrana ewes in gestation and lactation

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