Serum Proteins and Thyroxine-Protein Interaction in Early Human Fetuses

Andreoli, M; Robbins, Jacob

doi:10.1172/jci104557

Cited by 50 publications

(15 citation statements)

References 25 publications

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“…It is possible, however, that with more concentrated serum extracts in the younger fetuses, thyroxine could be identified earlier. Protein-bound iodine has been detected in fetal sera as early as 13 wk gestation ( 16). Thyroxine-binding globulin and thyroxine-binding prealbumin have been identified as early as 74 days estimated gestational age (16).…”

Section: Methodsmentioning

confidence: 99%

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Observations on the maturation of thyroid function in early fetal life

Greenberg¹,

Czernichow²,

Reba³

et al. 1970

J. Clin. Invest.

119

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ABSTRA CT Serum samples were obtained from 21 normal human fetuses after therapeutic abortion for psychiatric indications. Fetal crown-rump length ranged from 5.2 to 22.5 cm, corresponding to the gestational age of 65-168 days.Serum thyroxine, assayed by a modification of the Murphy-Pattee method, was identified in the second' smallest fetus examined at 78 days gestation. Thereafter it increased rapidly, maintaining a significant linear correlation with crown-rump length until term (r = 0.800, P < 0.001). Free thyroxine (FT4) also increased in a linear relation to gestational age (r = 0.908, P < 0.001), but reached term levels by 18-20 wk. Radioimmunoassayable thyroid-stimulating hormone (TSH) was detected at 78 days gestation. Levels increased rapidly with advancing gestation, so that by 16 wk almost all were within the range of term infants. After 16 wk gestation, levels were usually greater than 4.0 MU/cc, higher than that seen in normal children.No correlation was demonstrated between the serum TSH levels and total thyroxine. TSH and FT4, however, increased in a parallel manner with a significant positive correlation. This suggested that fetal TSH secretion was responsive to FT4 levels from very early in gestation, possibly as early as 11 wk.Thyroxine-binding globulin (TBG) was detected in a fetus of 78 days gestation (1.4 Ag/100 ml). Levels increased rapidly, paralleling the rise in serum thyroxine and maintaining a linear correlation with crownrump length (r = 0.864, P < 0.001). Thyroxine-binding prealbumin binding capacity (TBPA) in fetuses 14-24 wk gestation was comparable with that seen at term.When examining the distribution of tracer amounts of thyroxine-"31I (T4-"'I) between the thyroxine-binding

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Section: Methodsmentioning

confidence: 99%

“…Protein-bound iodine has been detected in fetal sera as early as 13 wk gestation ( 16). Thyroxine-binding globulin and thyroxine-binding prealbumin have been identified as early as 74 days estimated gestational age (16). Specimens from younger fetuses have not been examined for these thyroxinebinding proteins.…”

Section: Methodsmentioning

confidence: 99%

Observations on the maturation of thyroid function in early fetal life

Greenberg¹,

Czernichow²,

Reba³

et al. 1970

J. Clin. Invest.

119

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“…The electrophoretic mobility of this serum fetoprotein at pH 8.6 is that of an a-globulin, the protein migrating somewhat slower than serum albumin but faster than the serum a1-globulins at this pH (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). As is well known, fetal calf serum also contains an a-globulin, the mucoprotein fetuin (11), which is not found in adult bovine serum.…”

mentioning

confidence: 94%

“…This protein has been observed in the serum of the conceptus as early as 10 to 14 weeks in the gestational period, and it has been reported that the serum concentration of the protein decreases as gestation continues (1)(2)(3)(4)(5)(6)(7). Most investigators have been unable to detect the protein in fetuses older than 4 to 6 months' gestation (1)(2)(3)(4)(5)(6)8) or in prematurely born infants (5), but others have reported its presence in cord serum and in the serum of the newborn during the first week of life (9,10).…”

mentioning

confidence: 99%

Serum alpha-fetoprotein, albumin, and gamma-G-globulin in the human conceptus.

Gitlin¹,

Boesman²

1966

J. Clin. Invest.

406

101

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“…The protein disappears from the serum of the newborn infant with a half-life of approximately 3.5 days. Serum a-fetoprotein is not found beyond the neonatal period, and it is not present in the serum of the pregnant woman (2)(3)(4)(5)(6)(7)(8)(9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

Sites of Serum α-Fetoprotein Synthesis in the Human and in the Rat*

Gitlin¹,

Boesman²

1967

J. Clin. Invest.

293

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Summary. Selected tissues from human embryos of 6 to 9 weeks' gestation, from rat fetuses of 15 days' gestation, and from rats 2 days of age were incubated with 14C-labeled amino acids. Immunoelectrophoresis of the culture fluid after incubation, using rabbit antisera against human and rat fetal serum proteins, followed by radioautography revealed that: 1) Radioactive a-fetoprotein was present in cultures of human liver, rat liver, and rat yolk sac, but not in cultures of human or rat brain, lung, heart, kidney, intestines, skeletal muscle, skin, or placenta; human yolk sac was not studied. 2) Radioactive transferrin was also present in rat yolk sac cultures, and the same protein was found in rat liver cultures as well. 3) Rat liver and rat placenta cultures both produced radioactive serum Ra2-globulin.Serum a-fetoprotein concentrations in the rat declined abruptly after birth to approximately half of the prenatal level by 2 to 3 days of age, in accord with the loss of the fetal membranes at delivery; the a-fetoprotein level then remained relatively constant until the rat was 6 to 8 days of age, after which synthesis of the protein was increasingly suppressed. IntroductionAt some time before the seventh week of gestation, an a-globulin, which has been termed a-fetoprotein, appears in the serum of the human embryo (1). Synthesis of the protein increases rapidly, and by 13 weeks' gestation serum concentrations of approximately 300 mg per 100 ml are attained. The total amount of serum a-fetoprotein synthesized by the conceptus continues to increase until 20 weeks' gestation, but the serum concentration of the protein decreases after the thirteenth week, due to a rate of fetal growth greater than the rela--tive increase in the amount of a-fetoprotein synthesized. After 20 weeks' gestation, total a-fetoprotein synthesis becomes relatively constant until

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Serum Proteins and Thyroxine-Protein Interaction in Early Human Fetuses

Cited by 50 publications

References 25 publications

Observations on the maturation of thyroid function in early fetal life

Observations on the maturation of thyroid function in early fetal life

Serum alpha-fetoprotein, albumin, and gamma-G-globulin in the human conceptus.

Sites of Serum α-Fetoprotein Synthesis in the Human and in the Rat*

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