Changes in the levels of growth hormones, insulin, cortisol, thyroxine and somatomedin-C/IGF-1, with increasing gestational age in the fetal pig, and the effect of thyroidectomy in utero

. 1993. Postnatal thyroxine status of piglets in response to prenatal thyroxine infusion of the sow. Can. J. Anim. . Fifteen piegnant primiparous sows were infused intravenously with either 0 (T10), 25 (T425), or 50 (Ta50) mg thyroxine (To) I-'infusion de To a accru (P < 0,05) les niveaux plasmatiques de la"truie durant toute la dur6e de I'infusion. Toutefois, le traitement pr6natal des truies n'a pas laiss6 de diff6rences clans les concentrations plasmatiques de T.1 chez les porcelets. Il n'avait pas non plus d'effet sur la durde de I'intervalle nalssance-premibre t6t6e. Dans tous les groupes, les porcelets avaient les mdmes temp6ratures rectales dans les 2 minutes suivant la naissance (P < 0,05). L'exposition au fioid a caus6 une baisse non significative des temp6ratures rectales et cutan6es chez tous les porcelets. Ces observations portent ir conclure que I'administration de To d la truie gestante n'influe pas sur I'intervalle naissance-piemibre t6t6e, sur l'aptitude thermor6gulaturice ou sur les performances ult6rieures des porcelets, vraiiemblablement d cause du faible taux de migration de [a thyroxine ) travers le placenia.

show abstract

“…In view of our findings and the evidence shown in humans, the results of Spencer et al (1989) are difficult to erplain.…”

Section: Methodscontrasting

confidence: 63%

Postnatal thyroxine status of piglets in response to prenatal thyroxine infusion of the sow

Bate¹,

Finsten²,

Crossley³

1993

Can. J. Anim. Sci.

View full text Add to dashboard Cite

show abstract

“…A major objective of this study was to validate our fetal-T4 model by determining the pattern ofT4 release from pellets and subsequent uptake into the blood. A pattern of serum T4 levels without a large peak i.e., steady state, is preferred since this is a typical or normal pattern for fetal serum T4levels (31). Data herein clearly show that serum T4 levels did not peak and were steady from one sampling period to another indicating a steady state pattern of release.…”

Section: Discussionmentioning

confidence: 70%

Ontogeny of the Response to Thyroxine (T₄) in the Porcine Fetus: Interrelationships Between Serum T₄, Serum Insulin‐Like Growth Factor‐1 (IGF‐1) and Differentiation of Skin and Several Adipose Tissues

Hausman

Wright

1996

Obesity Research

View full text Add to dashboard Cite

HAUSMAN, GARY J AND J THOMAS WRIGHT.Ontogeny of the response to thyroxine (T4) in the Porcine fetus: interrelationships between serum T4' serum insulin-like growth factor-I (lGF-l) and differentiation of skin and several adipose tissues. Obes Res.l996; The temporal aspect of thyroxine (T4) enhanced development of several fetal adipose tissue depots (locations) and skin was examined in the present study. On day 70 of gestation pig fetuses were either hypophysectomized (hypox), hypoxed and implanted with T4 pellets or left intact (control). Subsequently, fetuses were removed for study at either 73, 75, 80, 85 and 90 days of gestation. Serum levels of T4 and insulin-like growth factor I (lGF-1) were significantly elevated by T4 after 3 days of treatment and throughout the study. T4 treatment enhanced development of skin, inner and outer subcutaneous (SQ) adipose tissue and adipocyte lobules around hair follicles (HFL's) but degree of response and response time were tissue or depot dependent. The T4 response time was shortest for skin and HFL's, longest for inner SQ and intermediate for the outer SQ. Considering the entire treatment period, magnitude of the T4 response was much greater for skin and HFL's than for outer and inner SQ tissues.

show abstract

“…In species with little, if any, placental transfer of maternal thyroid hormones, such as sheep, goats, horses, and pigs, hypothyroidism induced congenitally or by surgical ablation of the fetal thyroid gland(s) causes growth restriction of the fetus (Table 2; Spencer et al 1989, Piosik et al 1997, Allen et al 1998. These studies show that fetal thyroid hormones are required for both accretion of fetal mass and differentiation of specific cell types, such as the wool or hair follicles, at critical stages of development well before term (Table 2; Hopkins & Thorburn 1972, Hausman 1992.…”

Section: Thyroid Hormones and Fetal Growthmentioning

confidence: 99%

Thyroid hormones in fetal growth and prepartum maturation

Forhead

Fowden

2014

Journal of Endocrinology

342

270

View full text Add to dashboard Cite

The thyroid hormones, thyroxine (T 4 ) and triiodothyronine (T 3 ), are essential for normal growth and development of the fetus. Their bioavailability in utero depends on development of the fetal hypothalamic-pituitary-thyroid gland axis and the abundance of thyroid hormone transporters and deiodinases that influence tissue levels of bioactive hormone. Fetal T 4 and T 3 concentrations are also affected by gestational age, nutritional and endocrine conditions in utero, and placental permeability to maternal thyroid hormones, which varies among species with placental morphology. Thyroid hormones are required for the general accretion of fetal mass and to trigger discrete developmental events in the fetal brain and somatic tissues from early in gestation. They also promote terminal differentiation of fetal tissues closer to term and are important in mediating the prepartum maturational effects of the glucocorticoids that ensure neonatal viability. Thyroid hormones act directly through anabolic effects on fetal metabolism and the stimulation of fetal oxygen consumption. They also act indirectly by controlling the bioavailability and effectiveness of other hormones and growth factors that influence fetal development such as the catecholamines and insulin-like growth factors (IGFs). By regulating tissue accretion and differentiation near term, fetal thyroid hormones ensure activation of physiological processes essential for survival at birth such as pulmonary gas exchange, thermogenesis, hepatic glucogenesis, and cardiac adaptations. This review examines the developmental control of fetal T 4 and T 3 bioavailability and discusses the role of these hormones in fetal growth and development with particular emphasis on maturation of somatic tissues critical for survival immediately at birth.

show abstract

Changes in the levels of growth hormones, insulin, cortisol, thyroxine and somatomedin-C/IGF-1, with increasing gestational age in the fetal pig, and the effect of thyroidectomy in utero

Cited by 15 publications

References 19 publications

Postnatal thyroxine status of piglets in response to prenatal thyroxine infusion of the sow

Postnatal thyroxine status of piglets in response to prenatal thyroxine infusion of the sow

Ontogeny of the Response to Thyroxine (T₄) in the Porcine Fetus: Interrelationships Between Serum T₄, Serum Insulin‐Like Growth Factor‐1 (IGF‐1) and Differentiation of Skin and Several Adipose Tissues

Thyroid hormones in fetal growth and prepartum maturation

Contact Info

Product

Resources

About

Changes in the levels of growth hormones, insulin, cortisol, thyroxine and somatomedin-C/IGF-1, with increasing gestational age in the fetal pig, and the effect of thyroidectomy in utero

Cited by 15 publications

References 19 publications

Postnatal thyroxine status of piglets in response to prenatal thyroxine infusion of the sow

Postnatal thyroxine status of piglets in response to prenatal thyroxine infusion of the sow

Ontogeny of the Response to Thyroxine (T4) in the Porcine Fetus: Interrelationships Between Serum T4, Serum Insulin‐Like Growth Factor‐1 (IGF‐1) and Differentiation of Skin and Several Adipose Tissues

Thyroid hormones in fetal growth and prepartum maturation

Contact Info

Product

Resources

About

Ontogeny of the Response to Thyroxine (T₄) in the Porcine Fetus: Interrelationships Between Serum T₄, Serum Insulin‐Like Growth Factor‐1 (IGF‐1) and Differentiation of Skin and Several Adipose Tissues