Serum concentrations of thyroxine-binding globulin, prealbumin and albumin in healthy fullterm, small-for-gestational age and preterm newborn infants.

Simultaneous serum concentrations of thyroxine-binding globulin (TBG), prealbumin (TBPA) and albumin (Alb) were measured in 130 fullterm, 32 small-for-gestational age and 25 preterm infants during their first six days of life. In all infants serum concentrations of TBG were higher and serum TBPA and Alb were lower than in male adults. Even higher serum TBG levels were found in the mothers. There was no correlation between serum concentrations in paired maternal and cord sera. In infants with birth weights appropriate for gestation serum TBG, TBPA, and Alb concentrations increased progressively with gestational age. In small-for-gestational age infants born at term serum concentrations of TBG and Alb were lower than those in fullterm, but higher than those in premature newborns. Serum TBPA in small-for-gestational age babies was even lower than seen in prematures. A positive correlation was found between thyroid hormones and TBG concentrations, not between serum TBPA and thyroid hormones. The ratios between serum concentration of thyroid hormones and proteins might indicate that more thyroid hormonebinding sites are occupied in fullterm than in low birth-weight newborns. However, the main reason for the different serum levels of thyroid hormones in fullterm, small-for-gestational age and preterm babies is probably the various serum TBG concentrations demonstrated in these infants.     

CHANGES IN SERUM CONCENTRATIONS OF THYROID HORMONES AND THYROID HORMONE-BINDING PROTEINS DURING EARLY INFANCY Studies in Healthy Fullterm, Small-for-gestational Age and Preterm Infants Aged 7 to 240 Days

Abstract. Serum concentrations of thyrotropin (TSH), thyroxine (T₄), triiodothyronine (T₃), thyroxine-binding globulin (TBG), prealbumin (TBPA) and albumin (Alb) were determined in 492 blood samples from 127 fullterm (FT), 91 small-for-gestational age (SGA) and 88 preterm (PT) healthy infants aged 7 to 240 days. Serum T ₄ decreased about 20% during the first month of life. In infants aged 7–49 days, serum T₄ concentrations were significantly lower in SGA than in FT infants, and even lower values were found in PT infants. Serum T ₃ increased 50–70% reaching maximal values by 50–79 days of life. Serum T₃ levels were higher in FT than in SGA infants throughout the observation period. In PT infants serum T₃ increased from low values to levels which exceeded those of SGA and FT infants by 120–240 days of life. Serum TSH level did not change with age and was 5 mU/1 in all infants. Serum TBG values were high compared to normal adult values and did not change significantly with age. Comparable serum TBG values were found in FT, SGA and PT infants. Serum TBPA increased with age. Serum TBPA increased gradually in FT infants. In SGA infants serum TBPA increased from low values to levels which by 120–240 days of life exceeded those of PT and FT infants. In PT infants a decrease in serum TBPA appeared before the rise commenced. Serum Alb increased gradually in FT, SGA and PT infants during the observation period. Serum Alb in PT infants aged 30–119 days was lower than those in FT infants with similar ages. These physiological changes in serum concentrations of thyroid hormones and hormone-binding proteins during early infancy should be considered when interpreting thyroid function tests in infants with various maturity.     

Changes in serum concentrations of thyroid hormones and thyroid hormone-binding proteins during early infancy. Studies in healthy fullterm, small-for-gestational age and preterm infants aged 7 to 240 days.

Serum concentrations of thyrotropin (TSH), thyroxine (T4), triiodothyronine (T3), thyroxine-binding globulin (TBG), prealbumin (TBPA) and albumin (Alb) were determined in 492 blood samples from 127 fullterm (FT), 91 small-for-gestational age (SGA) and 88 preterm (PT) healthy infants aged 7 to 240 days. Serum T4 decreased about 20% during the first month of life. In infants aged 7--49 days, serum T4 concentrations were significantly lower in SGA than in FT infants, and even lower values were found in PT infants. Serum T3 increased 50--70% reaching maximal values by 50--79 days of life. Serum T3 levels were higher in FT than in SGA infants throughout the observation period. In PT infants serum T3 increased from low values to levels which exceeded those of SGA and FT infants by 120--240 days of life. Serum TSH level did not change with age and was less than or equal to 5 mU/l in all infants. Serum TBG values were high compared to normal adult values and did not change significantly with age. Comparable serum TBG values were found in FT, SGA and PT infants. Serum TBPA increased with age. Serum TBPA increased gradually in FT infants. In SGA infants serum TBPA increased from low values to levels which by 120--240 days of life exceeded those of PT and FT infants. In PT infants a decrease in serum TBPA appeared before the rise commenced. Serum Alb increased gradually in FT, SGA and PT infants during the observation period. Serum Alb in PT infants aged 30--119 days was lower than those in FT infants with similar ages. These physiological changes in serum concentrations of thyroid hormones and hormone-binding proteins during early infancy should be considered when interpreting thyroid function tests in infants with various maturity.     

COMPARISONS BETWEEN SERUM CONCENTRATIONS OF THYROXINE AND THYROXINE-BINDING PROTEINS IN SAMPLES SIMULTANEOUSLY OBTAINED FROM CAPILLARY, PERIPHERAL VEIN, CENTRAL VEIN AND AORTA IN NEWBORN INFANTS

Abstract. Jacobsen, B. B. and Peitersen, B. (University Clinic of Paediatrics, Children's Hospital, Fuglebakken, Copenhagen, Denmark). Comparisons between serum concentrations of thyroxine and thyroxine-binding proteins in samples simultaneously obtained from capillary, peripheral vein, central vein and aorta in newborn infants. Acta Paediatr Scand, 68: 43, 1979.—A total number of 40 newborn infants with various maturity were studied: 13 babies without perinatal events, 19 infants recovered from transient diseases, 6 infants with idiopathic respiratory distress syndrome and 2 infants with asphyxia indicating artificial ventilation. Comparisons were performed between serum concentrations of thyroxine (T₄), thyroxine-binding globulin (TBG), prealbumin (TBPA) and albumin (Alb) in capillary versus peripheral vein, aorta versus central vein and, finally, in peripheral versus central veins. In healthy infants serum T₄ concentrations in capillary blood and peripheral vein did not differ significantly. Although serum concentrations of thyroid hormone-binding proteins tended to be increased in aortic compared to central venous specimens no statistically significant differences appeared. In infants in good clinical conditions serum T₄, TBG, TBPA, and Alb levels were 6–8% higher in peripheral than in central veins, possibly primarily due to a hemo-concentrating effect of venous stasis. Therefore, in evaluation of the thyroid variables in newborn infants the technique of blood sampling must be considered. In most infants with idiopathic respiratory distress syndrome and in one asphyxiated baby a remarkable tendency to a low serum TBG and T₄ concentration in peripheral compared to central vein samples, were observed.     

Comparisons between serum concentrations of thyroxine and thyroxine-binding proteins in samples simultaneously obtained from capillary, peripheral vein, central vein and aorta in newborn infants.

A total number of 40 newborn infants with various maturity were studied: 13 babies without perinatal events, 19 infants recovered from transient diseases, 6 infants with idiopathic respiratory distress syndrome and 2 infants with asphyxia indicating artificial ventilation. Comparisons were performed between serum concentrations of thyroxine (T4), thyroxine-binding globulin (TBG), prealbumin (TBPA) and albumin (Alb) in capillary versus peripheral vein, aorta versus central vein and, finally, in peripheral versus central veins. In healthy infants serum T4 concentrations in capillary blood and peripheral vein did not differ significantly. Although serum concentrations of thyroid hormone-binding proteins tended to be increased in aortic compared to central venous specimens no statistically significant differences appeared. In infants in good clinical conditions serum T4, TBG, TBPA, and Alb levels were 6--8% higher in peripheral than in central veins, possibly primarily due to a hemo-concentrating effect of venous stasis. Therefore, in evaluation of the thyroid variables in newborn infants the technique of blood sampling must be considered. In most infants with idiopathic respiratory distress syndrome and in one asphyxiated baby a remarkable tendency to a low serum TBG and T4 concentration in peripheral compared to central vein samples were observed.     

Serum concentrations of thyrotropin, thyroid hormones and thyroid hormone-binding proteins during acute and recovery stages of idiopathic respiratory distress syndrome.

A total number of 27 premature infants with idiopathic respiratory distress syndrome (IRDS) and 52 healthy controls with comparable gestational age and body weights were studied during the first month of life. In infants with IRDS a reduced thyrotropin (TSH) response to birth was suggested, as serum TSH was lower in IRDS patients than in controls during the first two days of life. Low serum concentrations of thyroid hormones were found in the acute stage of IRDS reaching minimal values by day 3--5. After that period an increase in thyroid hormone levels occurred. The serum T2 increased to the level of healthy prematures by day 6--10, whereas the serum T4 increased to normal levels by day 21--30. Serum concentrations of thyroxine-binding globulin (TBG) were significantly lower in IRDS patients than in healthy controls; a gradual increase to normal levels occurred during recovery. Serum prealbumin (TBPA) levels in IRDS infants increased rapidly after birth and exceeded levels of healthy infants. Serum albumin values were not significantly different in the two groups of infants. The serum T4/TBG ratios were low during recovery from IRDS.     

SERUM CONCENTRATIONS OF THYROTROPIN, THYROID HORMONES AND THYROID HORMONE BINDING PROTEINS DURING ACUTE AND RECOVERY STAGES OF IDIOPATHIC RESPIRATORY DISTRESS SYNDROME

Abstract. A total number of 27 premature infants with idiopathic respiratory distress syndrome (IRDS) and 52 healthy controls with comparable gestational age and body weights were studied during the first month of life. In infants with IRDS a reduced thyrotropin (TSH) response to birth was suggested, as serum TSH was lower in IRDS patients than in controls during the first two days of life. Low serum concentrations of thyroid hormones were found in the acute stage of IRDS reaching minimal values by day 3–5. After that period an increase in thyroid hormone levels occurred. The serum T₃ increased to the level of healthy prematures by day 6–10, whereas the serum T₄ increased to normal levels by day 21–30. Serum concentrations of thyroxine-binding globulin (TBG) were significantly lower in IRDS patients than in healthy controls; a gradual increase to normal levels occurred during recovery. Serum prealbumin (TBPA) levels in IRDS infants increased rapidly after birth and exceeded levels of healthy infants. Serum albumin values were not significantly different in the two groups of infants. The serum T₄/TBG ratios were low during recovery from IRDS.     

THYROXINE-BINDING GLOBULIN DEFICIENCY IN EARLY CHILDHOOD

ABSTRACT. Jacobsen, B. B., Hansted, L. C, Brandt, N. J., Haahr, J., Hummer, L., Munkner, T. and Sorensen, S. S. (Department of Paediatrics, Viborg Hospital, Children's Hospital Fuglebakken, Department of Paediatrics, Section of Clinical Genetics and Department of Nuclear Medicine, Rigshospitalet, Copenhagen, Denmark). Thyroxine-binding globulin deficiency in early childhood. Postnatal changes in serum concentrations of thyroid hormones and thyroid hormone-binding proteins. Acta Paediatr Scand, 70:155, 1981. –Serial determinations of serum thyroxine (T4), triiodothyronine (T3), thyrotropin(TSH), thyroid hormone-binding globulin (TBG), prealbumin (TBPA) and albumin were performed in a euthyroid girl with TBG deficiency and in her mother for a period of 22 months after delivery. At 8 days old the child had a serum TBG concentration around 50% of normal level which remained essentially unchanged during infancy. Total serum T4 and T3 concentrations were low, the free serum T4, free serum T3 and serum TSH concentrations were normal. The mother had received thyroid hormone from the age of 15 years. Her serum TBG level at 6 weeks post partum was similar to that of non-pregnant adults but decreased to about 50% of normal level, indicating a TBG deficiency. She remained euthyroid after withdrawal of T4 therapy. Serum TBPA and albumin concentrations were normal in mother and child. An X-linked inheritance of the TBG deficiency was suggested from a study of the family.     

Thyroxine-binding globulin deficiency in early childhood. Postnatal changes in serum concentrations of thyroid hormones and thyroid hormone-binding proteins

Serial determinations of serum thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH), thyroid hormone-binding globulin (TBG), prealbumin (TBPA) and albumin were performed in a euthyroid girl with TBG deficiency and in her mother for a period of 22 months after delivery. At 8 days old the child had a serum TBG concentration around 50% of normal level which remained essentially unchanged during infancy. Total serum T4 and T3 concentrations were low, the free serum T4, free serum T3 and serum TSH concentrations were normal. The mother had received thyroid hormone from the age of 15 years. Her serum TBG level at 6 weeks post partum was similar to that of non-pregnant adults but decreased to about 50% of normal level, indicating a TBG deficiency. She remained euthyroid after withdrawal of T4 therapy. Serum TBPA and albumin concentration were normal in mother and child. An X-linked inheritance of the TBG deficiency was suggested from a study of the family.     

SERUM LEVELS OF THYROTROPIN, THYROXINE AND TRIIODOTHYRONINE IN FULLTERM, SMALL-FOR-GESTATIONAL AGE AND PRETERM NEWBORN BABIES

Abstract. Simultaneous serum concentrations of TSH, total thyroxine (T₄) and triiodothyronine (T₃) were determined in 93 fullterm (FT), 37 small-for-gestational age (SGA) and 38 preterm (PT) babies with a postnatal age from 2 to 144 hours. In addition, TSH, T₄ and T₃ concentrations were measured in cord sera from 27 FT, 4 SGA and 5 PT babies and in venous blood from 20 mothers at delivery. Cord blood concentrations of TSH were higher and T₄ and T₃ concentrations were lower than seen in the mothers. Serum concentrations of TSH were high during the first day of life followed by a decline. There was no statistically significant difference between serum TSH concentrations of the three groups of newborns. On the 5th day of life no elevated serum TSH values were found in any of the groups (TSH<5mU/l). Serum concentrations of thyroid hormones increased after birth and reached maximum levels within 24 hours in all groups. The relative increases above cord level were of the same magnitude in the newborns: Two times for serum T₄ and six times for serum T₃. The thyroid hormone concentrations in blood samples from FT babies decreased from the second day of life, whereas in low birth weight newborns the decreases were more variable. The serum levels of T₄ and T₃ were significantly different in the three groups of newborns, the highest values were seen in FT and the lowest values in PT babies. In contrast, the ratios between molar serum concentrations of T₄ and T₃ were found to be highest in PT, lower in SGA and lowest in FT babies, approaching maternal values during the first week of life. The data are discussed with regard to hormone secretion, thyroxine-binding capacity and peripheral T₄ to T₃ conversion in the three groups of newborns. It is concluded that from day 5 after birth serum TSH determinations, alone or in combination with serum T₄, seem to be the method of choice in screening for congenital hypothyroidism.     

PITUITARY-THYROID RESPONSIVENESS TO THYROTROPIN-RELEASING HORMONE IN PRETERM AND SMALL-FOR-GESTATIONAL AGE NEWBORNS

Abstract. A dose of 40 μg TRH was injected intravenously in 12 preterm (PT) and 15 small-for-gestational age (SGA) babies (with advanced gestational ages) between 5 and 167 hours after birth. Serum-thyrotropin (TSH) was measured prior to and 30 and 180 min after TRH; serum-thyroxine (T₄) and serum-triiodothyronine (T₃) were measured prior to and 180 min after TRH. The percentage increase in serum-TSH in PT and SGA babies was comparable to that of fullterm newborns. The serum-TSH 30 min after TRH in SGA newborns was significantly correlated to basal TSH values, such a correlation could not be shown in the preterms. One SGA and four PT babies had a repeat TRH-test performed later in infancy: In all but one PT with a gestational age of 27 weeks the TSH rise was lower than in the neonatal period. The thyroid hormone responses after TRH were similar in the two groups of babies. The percentage increase above basal levels were: Median serum-T₃ increase about 46% and median serum-T₄ increase about 14%. It is concluded that in low-birth-weight newborn babies the pituitary TSH response to exogenous TRH was like that detected in fullterm newborns and more pronounced than later in infancy. The effect of endogenous TSH as measured by thyroid hormone increases was of the same magnitude as observed in fullterms and in adults.     

Pituitary-thyroid responsiveness to thyrotropin-releasing hormone in preterm and small-for-gestational age newborns.

A dose of 40 microgram TRH was injected intravenously in 12 preterm (PT) and 15 small-for-gestational age (SGA) babies (with advanced gestational ages) between 5 and 167 hours after birth. Serum-thyrotropin (TSH) was measured prior to and 30 and 180 min after TRH; serum-thyroxine (T4) and serum-triiodothyronine (T3) were measured prior to and 180 min after TRH. The percentage increase in serum-TSH in PT and SGA babies was comparable to that of fullterm newborns. The serum-TSH 30 min after TRH in SGA newborns was significantly correlated to basal TSH values, such a correlation could not be shown in the preterms. One SGA and four PT babies had a repeat TRH-test performed later in infancy: In all but one PT with a gestational age of 27 weeks the TSH rise was lower than in the neonatal period. The thyroid hormone responses after TRH were similar in the two groups of babies. The percentage increase above basal levels were: Median serum-T3 increase about 46% and median serum-T4 increase about 14%. It is concluded that in low-birth-weight newborn babies the pituitary TSH response to exogenous TRH was like that detected in fullterm newborns and more pronounced that later in infancy. The effect of endogenous TSH as measured by thyroid hormone increases was of the same magnitude as observed in fullterms and in adults.     

Postnatal thyroid function in low birth weight infants: A cross-sectional assessment of free thyroxine and thyroid hormone binding globulin

To investigate the significance of low serum thyroxine in premature infants, serum FT4, T4, TSH and TBG were measured in 7 infants with BW<1000 g, 8 infants with BW 1001 to 1350 g, 9 infants with BW 1351 to 2499 g, and 11 full-term infants.FT4 concentrations were lower in the LBW infants than in the FT infants. Percent FT4 values in the infants with BW<1000 g were the highest in the groups studied, so that FT4 concentrations in those infants did not fall proportionally with the marked T4 decrease. TBG concentrations were lower in the VLBW infants (相似文献   

Behavior of the concentration of triiodothyronine, thyroxine, thyrotropin and thyroxine-binding globulin in the serum of children with nephrotic syndrome

Concentrations of triiodothyronine, thyroxine, thyrotropin, thyroxine-binding globulin, urea, creatinine, cholesterol and total protein were determined in serum of six children (ages from 4 to 16 years) with nephrotic syndrome undergoing therapy. The results showed that with decreasing concentration of serum protein and increasing concentration of cholesterol the concentrations of thyroxine and thyroxine-binding globulin decreased whereas the concentration of thyrotropin was elevated. Improvement in the concentration of serum protein lead to an improvement of serum levels of thyroid hormones and thyroxine-binding globulin; concentrations of thyrotropin and cholesterol returned to values close to normal. Although triiodothyronine was decreased slightly it remained in the normal range thus preventing overt hypothyroidism.     

Thyroid function in fetus and mother during the second half of normal pregnancy

Thyroid hormones, thyroxine-binding globulin (TBG) and thryrotropin (TSH) concentrations were measured in 46 paired fetal and maternal blood samples collected between 17 and 36 weeks of gestation. The samples were selected retrospectively from fetuses that had undergone cordocentesis for prenatal diagnosis, had been found to be unaffected and confirmed healthy at birth. In maternal serum, total thyroxine (TT4) and triiodothyronine (TT3) concentrations were high, but free thyroxine (FT4) and free triiodothyronine (FT3) were within normal adult ranges; reverse T3 (RT3) increased and TSH levels decreased towards term. Fetal TT4, FT4, TT3, FT3, TBG and TSH levels significantly increased whereas RT3 sharply decreased with gestational age. The ratio of fetal TSH/FT4 significantly decreased, suggesting that the set point for negative feedback of pituitary TSH secretion is changing while the sensitivity of the thyroid gland to TSH increases throughout gestation. There was no significant correlation between the maternal and fetal TBG, TSH, TT4 and FT4, whereas maternal TT3 was positively correlated with fetal TT4, FT4, TT3 and FT3. Normal reference values for maternal and fetal iodothyronines, TBG and TSH throughout the second half of gestation provide insight into fetal thyroid development and may be useful for prenatal diagnosis.     

Increased risk of primary hypothyroidism in preterm infants

Serum levels of thyroid stimulating hormone, thyroxine, triiodothyronine, free T4, thyroxine-binding globulin, reverse T3, and the TSH secretory areas and peak T3 after intravenous injection of 40 micrograms thyrotropin-releasing hormone were determined weekly from day 5 to 6 to 11 weeks of age in 42 unselected full-term and 61 preterm Belgian infants. The results on day 5 indicated a progressive deficit of thyroid function related to the degree of prematurity. In 92 infants this deficit progressively decreased with age and disappeared at 5 to 7 weeks. However, 11 infants developed biochemical evidence of overt but transient hypothyroidism. Belgian neonates are relatively iodine deficient, and this factor affects the constitution of iodine stores within the thyroid gland: (1) the urinary concentrations of iodine in the 103 infants studied in Belgium were markedly lower than in 30 infants from California; and (2) The iodine concentration of the thyroid gland in preterm infants who died during the 10 first days of life was almost three times lower in Brussels than in Toronto. The results indicate that, in Belgium, the effects of relative iodine deficiency on thyroid function are superimposed on and mask the physiologic state of tertiary hypothyroidism in prematurity.     

Neonatal infections: I—Maternal and cord serum IgG levels in relation to gestation and intrauterine growth

Fifty low birth weight babies (both preterms and intrauterine growth retarded) and their mothers were the subjects of the study. Ten fullterm babies weighing more than 3.0 kg and their mothers served as controls. The cord serum IgG levels were significantly lower in preterm babies compared to fullterm appropriate for gestational age (FT-AGA) and fullterm intrauterine growth retarded (FT-IUGR) babies. The cord serum IgG levels were not significantly different between FT-AGA and FT-IUGR babies. The maternal serum IgG levels were significantly higher than the cord serum IgG levels in preterm group whereas in fullterm AGA and IUGR groups cord serum IgG levels were significantly higher then the maternal serum IgG levels. There was no correlation between maternal and cord serum IgG levels. The cord serum IgG levels were significantly correlated with gestation even after controlling birth weight. The correlation between cord serum IgG levels and birth weight disappeared once qestation was controlled.     

The Effect of Non-Nutritive Sucking on Plasma Insulin, Gastrin, and Somatostatin Levels in Infants

ABSTRACT. The aim of the present investigation was to study the effect of non-nutritive sucking on plasma levels of insulin, gastrin, and somatostatin in infants. These hormones were measured with radioimmunoassay in plasma collected from fullterm and preterm infants sucking a pacifier. In fullterm infants, sucking caused a significant increase of insulin levels from 13 ± 10 μU/ml to 40 ± 36 μU/ml and 21 ± 17 μU/ml after 45 sec and 5 min respectively, from when the infants started sucking. A similar pattern was seen in preterm infants. In contrast, gastrin and somatostatin levels were not significantly affected. We suggest that sucking causes an activation of the vagal nerve, which results in the release of insulin. We also suggest that in infants, oral feeding is superior to bolus feeding, since in the latter case no vagal activation and consequently no release of hormones with anabolic properties occurs.     

Concentration levels of thyroxine binding globulin and thyroxine in the blood of euthyroid children. Reliability and diagnostic value of the T4/TBG quotiens--establishing reference values

The most important transportprotein for thyroxine (T4) is the thyroxine-binding globulin (TBG). This protein and T4 were determined using the radioimmunoassay method in bloodserum of 443 euthyreotic children. The age-specific analysis showed high TBG and T4 concentrations in the postnatal phase, nearly constancy between 1. and 9. years with concentrations in the upper physiological range of adults, elevation of the values in the age of 10/11. years and definite attainment of the normal range for adults at 12/13. years. The importance of the T4/TBG quotient for thyroid gland diagnostics was discussed.     

Thyroid function in children with cystic fibrosis

Serum concentrations of T4, T3, reverse T3 (rT3), TSH, Thyroxine binding globulin (TBG) and Thyroxine binding prealbumin (TBPA) were measured and a TRH-stimulation test was performed in 10 iodide untreated children affected by cystic fibrosis (CF) and in 84 controls.As compared to the controls, CF patients had lower T4 and rT3, similar T3 and TBG and increased T3:T4 ratios. They also had lower TBPA, but this could not account for the low T4. Finally they had higher basal and TRH-stimulated TSH. Our results indicate subclinical hypothyroidism in CF. The mechanisms responsible for this situation are not elucidated by our data.Presented in part at the 41st Meeting of the Italian Society of Pediatrics, October, 22–25, 1981, Bologna, Italy