Effect of fetal thyroidectomy on brown adipose tissue and thermoregulation in newborn lambs

Schermer, S. J.; Bird, John J.; Lomax, M.A.; Shepherd, David; Symonds, Michael

doi:10.1071/rd9960995

Cited by 67 publications

(61 citation statements)

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“…This occurred 2 days after colonic temperature was observed to be at a basal value of 39 3°C and plasma T3 concentrations increased to a maximal mean value above 10 nM. We have previously observed a critical interaction between plasma thyroid hormones, BAT postnatal lambs (Symonds et al 1989;Clarke, Bird, Lomax & Symonds, 1996;Schermer et al 1996), although in all these studies low plasma T3 concentrations were associated with reduced BAT activity and hypothermia. The (Jacobsson, Muhleisen, Cannon & Nedergaard, 1994).…”

Section: Discussionmentioning

confidence: 89%

“…The ability to maximize BAT function after birth is important clinically, since this can be compromised by Caesarean section birth (Christensson et al 1993;Clarke et al 1997b), and also agriculturally, since a high proportion of the 1-4 million annual lamb deaths in the British sheep industry are due to hypothermia (Slee, 1979). Thyroid hormones appear to have a critical role in maintaining heat production within BAT because low plasma thyroid hormone concentrations during early postnatal life are associated with an increased reliance on shivering thermogenesis and unexpected death (Symonds, Andrews & Johnson, 1989;Schermer, Bird, Lomax, Shepherd & Symonds, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Adipose Tissue Development During Early Postnatal Life in Ewe-Reared Lambs

Clarke¹,

BUSS²,

JUNIPER³

et al. 1997

Exp. Physiol.

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SUMMARYThis study examines the precise time course that brown adipose tissue (BAT) takes to adopt the characteristics of white adipose tissue in postnatal lambs. Perirenal adipose tissue was sampled from ewe-reared lambs within 1 h of birth and at 1, 2, 4, 7, 14, 21 and 30 days of age and analysed for the amount of mRNA for uncoupling protein (UCP), the amount and activity of UCP, and protein, mitochondrial protein and lipid content. This was combined with measurements of colonic temperature and jugular venous plasma concentrations of thyroid hormones and insulinlike growth factor-I (IGF-1). Over the first 4-7 days of age, large quantities of UCP mRNA were associated with a peak in plasma triiodothyronine concentration at 2 days of age followed by a maximal amount and activity of UCP at 4 days and a basal colonic temperature of 39 3°C. Between 7 and 30 days there was a large increase in lipid deposition as the amount and activity of UCP and the amount of UCP mRNA declined to basal values and colonic temperature was maintained at 40 'C. A significant positive relationship between perirenal adipose tissue lipid content and plasma IGF-1 concentration was observed throughout the study period. It is concluded that ovine adipose tissue maturation occurs in two distinct phases over the first month of life. The precise time scale of this process could be regulated in part by the lamb's body temperature which determines whether adipose tissue is required for heat production (i.e. BAT) or as an endogenous energy source (i.e. white adipose tissue).

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Adipose Tissue Development During Early Postnatal Life in Ewe-Reared Lambs

Clarke¹,

BUSS²,

JUNIPER³

et al. 1997

Exp. Physiol.

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“…The increased availability of active T3 is important for the latter phases of tissue differentiation. The functional development of brown adipose tissue allows to optimise non-shivering thermogenesis, thus permitting an adequate thermoregulation in the newborn (Schermer et al, 1996). Therefore, UCP1, induced by TH, is of primary importance for the transition from foetal to neonatal life, when cellular energy and thermoregulatory requirements are at maximal rates .…”

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confidence: 99%

Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

Todini

2007

Animal

193

142

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Appropriate thyroid gland function and thyroid hormone activity are considered crucial to sustain the productive performance in domestic animals (growth, milk or hair fibre production). Changes of blood thyroid hormone concentrations are an indirect measure of the changes in thyroid gland activity and circulating thyroid hormones can be considered as indicators of the metabolic and nutritional status of the animals. Thyroid hormones play a pivotal role in the mechanisms permitting the animals to live and breed in the surrounding environment. Variations in hormone bioactivity allow the animals to adapt their metabolic balance to different environmental conditions, changes in nutrient requirements and availability, and to homeorhetic changes during different physiological stages. This is particularly important in the free-ranging and grazing animals, such as traditionally reared small ruminants, whose main physiological functions (feed intake, reproduction, hair growth) are markedly seasonal. Many investigations dealt with the involvement of thyroid hormones in the expression of endogenous seasonal rhythms, such as reproduction and hair growth cycles in fibre-producing (wool, mohair, cashmere) sheep and goats. Important knowledge about the pattern of thyroid hormone metabolism and their role in ontogenetic development has been obtained from studies in the ovine foetus and in the newborn. Many endogenous (breed, age, gender, physiological state) and environmental factors (climate, season, with a primary role of nutrition) are able to affect thyroid activity and hormone concentrations in blood, acting at the level of hypothalamus, pituitary and/or thyroid gland, as well as on peripheral monodeiodination. Knowledge on such topics mirror physiological changes and possibly allows the monitoring and manipulation of thyroid physiology, in order to improve animal health, welfare and production.Keywords: goats, nutrition, seasons, sheep, thyroid hormones IntroductionAppropriate thyroid gland function and activity of thyroid hormones (TH) are considered crucial to sustain the productive performance in domestic animals (growth, milk, hair fibre production) and circulating TH can be considered as indicators of the metabolic and nutritional status of the animals (Riis and Madsen, 1985;Todini et al., 2007). Changes of blood TH concentrations are an indirect measure of the changes in thyroid gland activity. Many papers report marked seasonal variation in thyroid activity and in blood TH concentration. These hormone variations are particularly important in the free-ranging and grazing animals, whose main physiological functions (feed intake, reproduction, hair growth) are markedly seasonal. This is the case of small ruminants traditionally reared. Such variations in hormone concentration, in fact, allow the animals to adapt their metabolic balance to different environmental conditions, variations in nutrient requirements and availability, and to homeoretic changes during different physiological stages.The present paper aims to re...

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“…UCP1 content was measured, with 10 mg mitochondrial protein run on 12% SDS gel, which was transferred onto a membrane (Imobilon, Millipore, Molsheim, France) and incubated for 1 h with the UCP1 antibody (1/10 000 dilution; Schermer et al 1996) followed by 1 h of incubation with a donkey anti-rabbit secondary antibody (1/2000 dilution; Abcam, Paris, France; ab16284). Specificity of detection was confirmed using non-immune rabbit serum (1/10 000 dilution).…”

Section: Laboratory Analysismentioning

confidence: 99%

“…An avidin-biotin blocking kit (Vector Labs, Peterborough, UK) was used to block endogenous biotin, and 20% normal goat serum was used to prevent non-specific binding. The slides were incubated with the UCP1 antibody (Schermer et al 1996) diluted 1:10 000 in PBS-Tween overnight at 4 8C. A biotinylated secondary antibody (BA-1000; Vector Labs) was diluted 1:400 in PBS-Tween and applied for 30 min at room temperature and then incubated for the same time period with Vectastain Elite ABC Reagent (Vector Labs), after which the antibody was visualised using a DAB substrate kit (SK-4100; Vector Labs).…”

Section: Laboratory Analysismentioning

confidence: 99%

UCP1 is present in porcine adipose tissue and is responsive to postnatal leptin

Mostyn¹,

Attig²,

Larcher³

et al. 2014

Journal of Endocrinology

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Intrauterine growth restriction (IUGR) may be accompanied by inadequate thermoregulation, especially in piglets that are not considered to possess any brown adipose tissue (BAT) and are thus entirely dependent on shivering thermogenesis in order to maintain body temperature after birth. Leptin can stimulate heat production by promoting non-shivering thermogenesis in BAT, but whether this response occurs in piglets is unknown. Newborn female piglets that were characterised as showing IUGR (mean birth weight of approximately 0.98 kg) were therefore administered injections of either saline or leptin once a day for the first 5 days of neonatal life. The dose of leptin was 0.5 mg/kg, which is sufficient to increase plasma leptin by approximately tenfold and on the day of birth induced a rapid increase in body temperature to values similar to those of normal-sized 'control' piglets (mean birth weight of w1.47 kg). Perirenal adipose tissue was then sampled from all offspring at 21 days of age and the presence of the BAT-specific uncoupling protein 1 (UCP1) was determined by immunohistochemistry and immunoblotting. UCP1 was clearly detectable in all samples analysed and its abundance was significantly reduced in the IUGR piglets that had received saline compared with controls, but was raised to the same amount as in controls in those IUGR females given leptin. There were no differences in gene expression between primary markers of brown and white adipose tissues between groups. In conclusion, piglets possess BAT that when stimulated exogenously by leptin can promote increased body temperature. IntroductionBrown adipose tissue (BAT) is essential for effective adaptation to cold exposure of the extra-uterine environment in precocial species such as sheep in which there is rapid activation of BAT around the time of birth (Clarke et al. 1997). In pigs, however, it has long been considered that BAT is not present (Trayhurn et al. 1989) and the newborn is Journal of Endocrinology Thematic ResearchA MOSTYN and others UCP1 and leptin in porcine 223:1 M31-M38http://joe.endocrinology-journals.org Ñ 2014 Society for Endocrinology DOI: 10.1530/JOE-14-0155Printed in Great BritainPublished by Bioscientifica Ltd.primarily dependent on shivering thermogenesis in muscle in order to prevent hypothermia at birth (Symonds & Lomax 1992). This due to an open reading frame on the BAT-specific uncoupling protein 1 (UCP1) gene in the porcine species meaning that UCP1 is not expressed (Berg et al. 2006). However, it has more recently been suggested that BAT is present in young piglets because of the different morphological appearances of adipocytes within perirenal adipose tissue in 2-week-old females (Attig et al. 2008). However, this remains to be confirmed by direct measurements of UCP1. Moreover, our understanding of BAT has now been transformed as a consequence of the discovery of beige adipocytes that express UCP1 at approximately 10% of the amount observed in classical BAT , Wu et al. 2013, but whether comparable depots are be pr...

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Effect of fetal thyroidectomy on brown adipose tissue and thermoregulation in newborn lambs

Cited by 67 publications

References 0 publications

Adipose Tissue Development During Early Postnatal Life in Ewe-Reared Lambs

Adipose Tissue Development During Early Postnatal Life in Ewe-Reared Lambs

Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

UCP1 is present in porcine adipose tissue and is responsive to postnatal leptin

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