Effects of food restriction on cortisol, TSH and iodothyronine concentrations in the plasma of the newborn lamb

Wrutniak, Chantal; Cabello, Gérard

doi:10.1051/rnd:19870512

Cited by 16 publications

(9 citation statements)

References 35 publications

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“…As this spontaneous ingestion was much larger than the quantity of colostrum given to our lambs (20 % of the birthweight), it is not surprising that neonatal changes in plasma glucose, urea, cortisol and iodothyronines levels recorded in this experiment were similar that observed in food restricted lambs in previous works (Wrutniak, 1985 ;Wrutniak and Cabello, 1987a) ; in particular, during the first 36 h of life, plasma glucose levels were low and urea levels rose ; a sharp decrease in plasma T4 and T3 levels occurred after 8 h post-pa!tum whereas plasma reverse T3 and cortisol concentrations increased transiently.…”

Section: Resultssupporting

confidence: 86%

“…In Infants, rats and lambs, suckling could affect plasma thyroid hormone levels (Stbrak et al, 1978 ;Koldovsky et al, 1980 ;Wrutniak and Cabello, 1987a) ; moreover, milk ingestion was generally lower in hypotrophic than in control lambs ; therefore, all the animals were removed from mothers and received limited amounts of a bovine colostrum pool in order to limit this variability (2.5 g/100 g birthweight 4, 8, 12, 16, 20, 24, 28 and 32 h post-partum and thereafter artificial milk ad libitum).…”

Section: Introductionmentioning

confidence: 99%

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Neonatal changes in plasma cortisol, free and total iodothyronine levels in control and hypotrophic lambs

Wrutniak¹,

Cabello²

1987

Reprod. Nutr. Dévelop.

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Summary. Neonatal changes in plasma free and total iodothyronines, cortisol, glucose and urea levels have been studied in 8 control (birthweight a 2.5 kg) and 16 hypotrophic lambs (birthweight < 2.5 kg) receiving limited amounts of colostrum during the first 36 h of life and then fed ad libitum. During the period of colostrum feeding, plasma glucose levels were low in both groups and increased after the onset of ad libitum feeding ; they were significantly lower in hypotrophic animals from birth to 36 h. Plasma urea levels increased during the period of colostrum feeding and decreased thereafter in all animals. At birth, they were significantly higher in hypotrophic lambs.Over the entire period studied (20 d), plasma levels of total T4, free T4, total T3 and free T3 were markedly lowered in hypotrophic lambs without alterations in the values of the T3/free T4 ratio. No differences could be observed in plasma reverse T3 and cortisol levels. For all blood parameters recorded, the neonatal changes were parallel in the two groups of lambs.In agreement with hypoglycemia and hyperuremia observed at birth in hypotrophic lambs, with the litter size recorded for each experimental group and with previous results, placental insufficiency linked to a large litter size gestation could be at the origin of low thyroid hormone levels.Introduction.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Neonatal changes in plasma cortisol, free and total iodothyronine levels in control and hypotrophic lambs

Wrutniak¹,

Cabello²

1987

Reprod. Nutr. Dévelop.

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“…The basal concentrations of both hormones at this early age were twoto threefold higher than basal concentrations at any other age for these lambs. Plasma cortisol concentrations increase several-fold in the ovine fetus late in pregnancy (Magyar et al 1980;McMillen et al 1987) and decrease threefold within 48 h following birth (Wrutniak and Cabello 1987). High levels of β-endorphin in newborn lambs may also be a normal occurrence since, in humans, plasma β-endorphin concentrations are high at birth and fall 75-80% during the next 24 h (Wardlaw et al 1979;Facchinetti et al 1982).…”

Section: Resultsmentioning

confidence: 99%

Cortisol and β-endorphin responses to physical and psychological stressors in lambs

Mears¹,

Brown²

1997

Can. J. Anim. Sci.

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. 1997. Cortisol and ␤-endorphin responses to physical and psychological stressors in lambs. Can. J. Anim. Sci. 77: 689-694. Plasma cortisol, β-endorphin, T3 and T4 were determined in lambs before, during and after exposure to stress in order to evaluate the potential use of these hormones to objectively measure stress responses. Lambs were exposed to tail-docking, castration, weaning, isolation, and restraint stress. Twelve ewe and 24 ram lambs were assigned to the experiment, with 12 of the ram lambs surgically castrated when 3-wk old. Tail docking within 24 h of birth did not (P > 0.05) elevate either plasma cortisol or β-endorphin. Castration markedly elevated (P < 0.001) plasma cortisol and β-endorphin within 15 min of surgery. Both hormones were highly elevated for the first 4 h . Plasma cortisol returned to control levels by 24 h whereas β-endorphin was still elevated (P < 0.05) 24 h after castration. Plasma cortisol levels were elevated for the first 60 min following weaning (P < 0.005) and again at 24 h after dam removal (P < 0.001). Plasma β-endorphin was not elevated (P > 0.05) any time during the 72 h following weaning. Plasma cortisol (P < 0.001) and β-endorphin (P < 0.05) were elevated during the first 60 min following the start of 1 h of isolation. Results were similar for partial and total isolation. No effects of isolation were found for the next 23 h. Plasma cortisol (P < 0.005) was elevated during the first 30 min following 4 min of shearing-like restraint, whereas plasma β-endorphin was elevated only at 7 min (P < 0.05) after restraint began. No further effects of restraint were found prior to termination of sample collection at 24 h. None of the stressors employed affected plasma concentrations of T3 and T4. This study has shown that measurements of plasma cortisol and β-endorphin in blood samples obtained before, during and after stress are useful in assessing stress in lambs. The painful stressor, castration, induced marked and prolonged elevations of both hormones, whereas psychological stressors elicited graded, short-term cortisol responses and limited β-endorphin responses.Key words: Cortisol, β-endorphin, physical stress, psychological stress, lambs Mears, G. J. et Brown, F. A. 1997. Réponse du cortisol et de la ␤-endorphine aux stressants physiques et psychologiques chez les agneaux. Can. J. Anim. Sci. 77: 689-694. Nous avons suivi les niveaux plasmatiques de cortisol, de β-endorphine, de T3 et de T4 chez les agneaux avant, pendant et après une exposition aux stress afin d'évaluer les possibilités d'utilisation de ces hormones comme mesure objective des réponses au stress. Des agneaux étaient exposés à la caudectomie, à la castration, au sevrage, à l'isolement et à la contention. Douze agneaux femelles et 24 agneaux mâles étaient utilisés, dont 12 agneaux mâles étaient castrés par voie chirurgicale à l'âge de 3 semaines. La caudectomie réalisée dans les 24 heures suivant la naissance ne causait pas de relèvement (P > 0,05) des niveaux plasmatiques de cortisol ou de β-endorphine. En r...

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“…In all animals studied, food restriction was associated with a considerable reduction of plasma T3 levels, such as in man (Burman et al, 1979;Marugo et ai., 1984;Suda et al 1978), calves (Blum & Kunz, 1981;Tveit & Larsen, 1983) and adult (Blum et al, 1980) or newborn sheep (Wrutniak & Cabello, 1987a). This decrease in T3 production could be explained not only by a lowered TSH secretion (Burger Hugues et aL, 1984;R6jdmark & Nygren, 1983;Tveit & Almlid, 1980;Wrutniak & Cabello, 1987a), but also by an inhibition of the peripheral conversion of T4 into T3 (Balsam & Ingbar, 1979;Chopra, 1980;Gavin & Moeller, 1983).…”

Section: Growth Hormone Does Not Always Stimulate Somatomedin Productionmentioning

confidence: 99%

Thyroid hormone and growth : relationships with growth hormone effects and regulation

Cabello¹,

Wrutniak²

1989

Reprod. Nutr. Dévelop.

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― For some years, research in the field of growth endocrinology has been mainly focused on growth hormone (GH). However, it appears that GH does not always control growth rate. For instance, it does not clearly influence intra-uterine growth : moreover, although the results of GRF or GH administration appear convincing in rats, pigs or heifers, this is not the case in chickens and lambs. In addition, GH does not always clearly stimulate somatomedin production, particularly diring food restriction and fetal life, and in hypothyroid animals or sex-linked dwarf chickens. In such situations, this phenomenon is associated with a reduced T3 production, suggesting a significant influence of thyroid function on GH action, and more generally, on body growth. In fact, numerous data demonstrate that thyroid hormone is strongly involved in the regulation of body growth. In species with low maturity at birth, such as the rat. T4 and T3 affect postnatal growth eleven days earlier than the appearance of GH influence. In contrast to GH, thyroid hormone significantly influences fetal growth in sheep. Moreover, the body growth rate is clearly stimulated by T3 in dwarf animals. In addition to its complex metabolic effects involved in the general mechanisms of body growth, thyroid hormone stimulates the production of growth factors, particularly EGF and NGF. Moreover, it affects GH and somatomedin production and also their tissue activity. All these results strongly suggest that it would be difficult to study GH regulation and physiological effects without taking thyroid function into account. body growth ― thyroid hormone ― GH ― GRF ― IGF Résumé ― Hormones thyroïdiennes et croissance. Interactions avec l'axe somatotrope. Depuis plusieurs années, les recherches concernant l'endocrinologie de la croissance sont particulièrement orientées sur l'hormone de croissance (GH). Il semble cependant que le GH ne contrôle pas la croissance dans toutes les situations. Ainsi, elle ne semble pas influencer la croissance intra-utérine; de plus, si les résultats de l'administration de GRF ou de GH sont convaincants chez le rat, le porc ou le bovin, ils s'avèrent plus décevants chez le poulet ou le mouton. D'autre part, la GH n'induit pas toujours une stimulation de la production de somatomédines, notamment pendant la vie intra-utérine, au cours de la restriction alimentaire, ainsi que chez les animaux hypothyroitiiens et chez les poulets nains (nanisme lié au sexe). Dans toutes ces situations particulières, la déficience de stimulation des somatomédines par la GH est associée à une production réduite de T3, ce qui suggère une influence significative de la fonction thyroïdienne sur les effets de la GH, et plus généralement sur la croissance. En fait, de nombreux résultats démontrent que les hormones thryoïdiennes sont impliquées dans la régulation de la croissance corporelle. Chez les espèces à faible maturité à la naissance telles que le rat, la T4 et la T3 influencent la croissance postnatale bien avant qu...

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Effects of food restriction on cortisol, TSH and iodothyronine concentrations in the plasma of the newborn lamb

Cited by 16 publications

References 35 publications

Neonatal changes in plasma cortisol, free and total iodothyronine levels in control and hypotrophic lambs

Neonatal changes in plasma cortisol, free and total iodothyronine levels in control and hypotrophic lambs

Cortisol and β-endorphin responses to physical and psychological stressors in lambs

Thyroid hormone and growth : relationships with growth hormone effects and regulation

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