Serum tri-iodothyronine, thyroxine, and thyrotrophin concentrations in newborns during the first 2 days of life.

Similä, S; Koivisto, Maila; Ranta, Tapio; Leppäluoto, Juhani; Reinilä, Matti; Haapalahti, J.

doi:10.1136/adc.50.7.565

Cited by 30 publications

(16 citation statements)

References 9 publications

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“…The increase in serum TSH following TRH stimulation is correlated with basal serum TSH concentrations, and is of the same magnitude as in adults subjects (8,22). A transitory increase in serum concentrations of TSH and thyroid hormones has previously been described (6,9,10,14,19) and is confirmed by this study. It is a well known fact that minor increases in thyroid hormone concentrations, in animals and in Arta Pzdiutr Srand 65 man, are able to inhibit the TSH release after TRH by negative feed-back at the pituitary level (16,17,18,20).…”

Section: Discussionsupporting

confidence: 88%

Thyrotropin Response to Thyrotropin‐releasing Hormone in Fullterm, Euthyroid and Hypothyroid Newborns

et al. 1976

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The serum concentration of thyrotropin (TSH) and the TSH response following thyrotropin-releasing hormone (TRH) were studied in 16 euthyroid babies from 16 to 172 hours after birth and in 2 primary hypothyroid babies, 3 and 28 days of age. Serum-TSH was measured before an intravenous injection of 40 mug TRH and after 30 and 180 min. In the euthyroid babies increased basal levels of TSH were seen shortly after birth, followed by a pronounced decline. The extent of TSH increase after TRH could be correlated with the basal levels, and the relative increase was comparable to that which occurs in adults. In the hypothyroid babies very high basal levels of serum-TSH were seen, 125 and 400 muU/ml respectively, with no further increase following TRH stimulation. It was concluded that in euthyroid fullterm newborn, the relative response of serum-TSH to TRH was equal to that of adults, in spite of elevated thyroid hormone concentrations. In the hypothyroid newborn very high levels of serum-TSH were seen and a supplementary TRH-test seems without diagnostic value in congenital hypothyroidism.

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Section: Discussionsupporting

confidence: 88%

Thyrotropin Response to Thyrotropin‐releasing Hormone in Fullterm, Euthyroid and Hypothyroid Newborns

et al. 1976

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“…Our results concerning the distribution of T4 and TSH levels in the cord blood confirm results reported by other authors (see review in Simila et al, 1975). Our findings do not confirm the relationship hypothesized by Walfish et al (1975) between the level of TSH in the cord and the duration of the delivery.…”

Section: Discussioncontrasting

confidence: 52%

Serum thyrotrophin determination on day 5 of life as screening procedure for congenital hypothyroidism.

Delange¹,

Camus²,

Winkler³

et al. 1977

Archives of Disease in Childhood

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SUMMARY In 327 newborns cord blood thyroxine (T4) was 118 0-4 ,ug/100 ml (SEM) (151 -9+ 5 1 nmol/l), and serum thyrotrophin (TSH) 6 7±10 ,U/ml. Variability was marked for both T4 and TSH. Remeasured in the same patients on the fifth day of life, the TSH level was 3'7 ±1-0 ,uU/ml, lower than at birth (P <0.001), while scattering of TSH values was much smaller, with 99.4% of values <12 ,uU/ml. TSH level at day 5 was therefore subsequently used as a screening procedure, considering 12 ,uU/ml as the upper limit of normal.In 14 of 1805 newborns (0-8 %), the TSH level exceeded this limit; in 3 raised TSH levels were subsequently confirmed, and hypothyroidism established by conventional criteria. One was a case of lingual thyroid (TSH >50 ,uU/ml) and the other 2 (TSH 27 and 50 ,uU/ml) iatrogenic caused by massive iodine impregnation of the mother (amniofetography). High TSH levels (160, 500, and 234 ,uU/ml) were also found in 3 hypothyroid infants aged less than one month who did not belong to the present screening programme.The striking difference between the TSH levels observed in normal and in hypothyroid infants during the first weeks of life suggests that serum TSH level at day 5 of life is the best parameter for systematic screening for congenital hypothyroidism.

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“…Thyroid hormones and metabolic rate during postnatal development Rearing temperature had no influence on plasma T3 concentration at 1 day of age, which was not unexpected, because over the first few hours and days of life thyroid hormone levels are primarily determined by the surge from the thyroid gland immediately after birth (Simila, Koivisto, Ranta, Leppaluoto, Reinila & Haapalahti, 1975;Polk, Callegari, Newnham, Padbury, Revicky, Fisher & Klein, 1987;Symonds et al 1994). At 1 day of age, most lambs increased metabolic rate during acute cold exposure without shivering, which is in contrast to the response observed in lambs born to underfed unshorn ewes .…”

Section: Lung Growth and The Recruitment Of Laryngeal Brakingmentioning

confidence: 92%

“…The mechanism of laryngeal braking is an example of the Breuer-Hering lung inflation reflex that has been repeatedly observed in infants over the first year of life (Rabbette, Fletcher, Dezateux, Soriano-Brucher & Stocks, 1994 (Simila, Koivisto, Ranta, Leppaluoto, Reinila & Haapalahti, 1975;Polk, Callegari, Newnham, Padbury, Revicky, Fisher & Klein, 1987;Symonds et al 1994). At 1 day of age, most lambs increased metabolic rate during acute cold exposure without shivering, which is in contrast to the response observed in lambs born to underfed unshorn ewes ).…”

Section: Lung Growth and The Recruitment Of Laryngeal Brakingmentioning

confidence: 99%

Environmental effects on thermoregulation and breathing patterns during early postnatal development in hand‐reared lambs

Symonds¹,

Andrews²,

Buss³

et al. 1995

Experimental Physiology

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SUMMARYThis study examines the effect of hand-rearing developing lambs in a warm (WR; 25°C) or cool (CR; 10-15°C) ambient temperature on the control of thermoregulation and breathing patterns, when maintained at a fixed level of nutrition over the first month of postnatal life. Measurements were made during non-rapid eye movement sleep whilst lambs were maintained for at least 1 h at warm (28-19°C) and cold (14-5°C) ambient temperatures at 1, 7, 14 and 30 days of age. All lambs were able to maintain normal body temperature, but oxygen consumption was higher in CR lambs at 14 and 30 days of age. At 1 day of age shivering was rarely observed in any lambs, but at 7 and 14 days of age more WR than CR lambs responded to cold exposure via shivering. Plasma concentrations of triiodothyronine were higher at 7 and 14 days of age in CR lambs. Breathing frequencies were similar in WR and CR lambs, and from 7 days of age the incidence of expiratory laryngeal braking was higher in warm compared with cold study temperatures. By 30 days of age the recruitment of this mechanism was greater in CR lambs. Mean growth rate was slower over the first week of postnatal life in CR compared with WR lambs. This difference decreased over the first month of life, as growth rate increased from 83 to 130 g day-' in the CR group but remained constant at approximately 150 g day-' in the WR lambs. Total weight of the lungs and heart, but not the liver, were lower at 1 month but not at 1 week of postnatal life in CR lambs. It is concluded that a modest decrease in the ambient temperature in which postnatal lambs are reared, when on a fixed feed intake, alters lung size, the recruitment of laryngeal braking and the control of body temperature.

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Serum tri-iodothyronine, thyroxine, and thyrotrophin concentrations in newborns during the first 2 days of life.

Cited by 30 publications

References 9 publications

Thyrotropin Response to Thyrotropin‐releasing Hormone in Fullterm, Euthyroid and Hypothyroid Newborns

Thyrotropin Response to Thyrotropin‐releasing Hormone in Fullterm, Euthyroid and Hypothyroid Newborns

Serum thyrotrophin determination on day 5 of life as screening procedure for congenital hypothyroidism.

Environmental effects on thermoregulation and breathing patterns during early postnatal development in hand‐reared lambs

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