The Effect of Estrogens Upon the Peripheral Metabolism of Thyroxine *†

Dowling, J. Thomas; Freinkel, Norbert; Ingbar, Sidney H.

doi:10.1172/jci104127

Cited by 87 publications

(36 citation statements)

References 37 publications

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“…As a consequence, the total concentration of hormone in the peripheral pool would decrease until a new steady state is reached when total hormonal disposal once again equals hormonal supply. Presumably, this would occur when the total disposal of hormone has returned 7 In our studies, these compounds were well tolerated by the patients and did not change the state of hydration, as judged from serial measurements of the hematocrit. In three instances, mild dyspepsia occurred, but this was readily relieved by antacids.…”

Section: In Vivo Studiesmentioning

confidence: 60%

“…This acceptance is based on studies demonstrating a consistent relationship between changes in the T4-binding activity of TBG, as assessed by electrophoresis in vitro and changes in the concentration and fractional turnover of T4 in vivo (6)(7)(8). From these observations, the conclusion has been drawn that TBG regulates the peripheral metabolism of T4 by limiting the concentration of unbound hormone.…”

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confidence: 99%

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The Effects of Noncalorigenic Congeners of Salicylate on the Peripheral Metabolism of Thyroxine*

Woeber¹,

Ingbar²

1964

J. Clin. Invest.

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Various experiments have indicated the presence in whole human serum of three major thyroxine (T4)-binding 1 proteins: T4-binding globulin (TBG), T4-binding prealbumin (TBPA), and albumin (1, 2). It is well established that, in vitro, TBG and TBPA are the major T4-binding proteins, whereas albumin is a relatively weak secondary carrier (3-5). These proteins interact with the hormone in a reversible binding equilibrium in which the majority of the hormone is bound but a measurable proportion is unbound or free. Free T4 has been suggested as the metabolically active component available to the cells in vivo for degradation, excretion, and initiation of hormonal action, with the bound hormone acting as a metabolically inert reservoir (3-5).The role of TBG in the transport and peripheral metabolism of T4 in man is well accepted. This acceptance is based on studies demonstrating a consistent relationship between changes in the T4-binding activity of TBG, as assessed by electrophoresis in vitro and changes in the concentration and fractional turnover of T4 in vivo (6-8). From these observations, the conclusion has been drawn that TBG regulates the peripheral metabolism of T4 by limiting the concentration of unbound hormone.The existence of TBPA as a normal constituent of human serum has been satisfactorily demonstrated by several techniques, and earlier doubts concerning its function in binding T4 at physiological pH have been dispelled (5, 9, 10). The role, if any, of -TBPA in regulating the peripheral metabolism of T4 in vivo has remained uncertain.* Submitted for publication December 9, 1963; accepted January 8, 1964. Supported in part by research grant Am-00267-10 from the National Institute of Arthritis and Metabolic Diseases, Bethesda, Md. hypermetabolism (19, 20), again the changes in T4 metabolism that these agents induce cannot necessarily be ascribed to an inhibition of T4-binding by TBPA.Previous reports have indicated that certain congeners -of salicylate do not uncouple oxidative phosphorylations in vitro (19) or stimulate oxygen consumption in vivo (21,22). We therefore made a search among these compounds for inhibitors of T4 binding by TBPA in order to study their effects on T4-metabolism in man. Methods and MaterialsIn vitro studiesThe effect of benzoic acid and a number of its hydroxy-, dihydroxy-, and amino-substituted derivatives 2 on the binding of T4 in normal serum was assessed by electrophoretic and dialysis techniques.

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Section: In Vivo Studiesmentioning

confidence: 60%

mentioning

confidence: 99%

The Effects of Noncalorigenic Congeners of Salicylate on the Peripheral Metabolism of Thyroxine*

Woeber¹,

Ingbar²

1964

J. Clin. Invest.

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“…Transferrin is a β 1 globulin which transports iron in the blood. This may be a consequence of increased estrogens during pregnancy, stimulating the rise in serum binding capacities, not only of iron, but also other hormones like thyroxine and corticosteroids (Dowling et al, 1960). It has also been suggested that raised serum transferrin levels may result in increased iron absorption (Fletcher et al, 1968).…”

Section: Discussionmentioning

confidence: 99%

Comparative study of serum ferritin levels after oral supplementation with ferrous sulphate and carbonyl iron in mild iron deficiency anemia in pregnancy

Chandrika¹,

Vasudha²

2010

International Journal of Biological and Chemical Sciences

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Iron supplementation is almost universally recommended during pregnancy to correct or prevent iron deficiency. Iron status can be assessed prepartum by estimating blood hemoglobin concentration, serum iron, serum total iron binding capacity (TIBC) and serum ferritin. This study attempts to know the therapeutic efficacy of the drugs, ferrous sulphate and carbonyl iron, in improving the iron stores to meet the increased demand during pregnancy. A comparative study was done in two groups of 36 pregnant women each. One group was supplemented with ferrous sulphate and the other group with carbonyl iron. The biochemical parameters assessing iron status, serum ferritin, serum iron and serum TIBC along with hemoglobin concentration were estimated before and after supplementation in both groups. Though not statistically significant, an increase was seen in the mean levels of serum ferritin in pregnant women who were supplemented with carbonyl iron compared to those who were supplemented with ferrous sulphate. Therefore, carbonyl iron can be preferred over ferrous sulphate in treating iron deficiency anemia in pregnancy, with added advantages of lesser side effects and shorter duration of therapy, which has been established in earlier studies.

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“…Though evidence is still fragmentary, there is general agreement that thyroid-hormone-plasma-protein interactions may control the action of the thyroid hormone by determining the level of its 'free' diffusible form in the circulation and hence its transfer to the peripheral tissues (Robbins & Rall, 1957, 1960Pitt-Rivers & Tata, 1959;Dowling, Freinkel & Ingbar, 1960). The concentration of free diffusible thyroxine in the blood would therefore play a major role in the thyroid-pituitary homoeostatic 12 G. MORREALE DE ESCOBAR AND F. ESCOBAR DEL REY mechanism, a system which is believed to be regulated so as to maintain a normal intracellular concentration and metabolism of the thyroid hormone.…”

Section: Discussionmentioning

confidence: 99%

The effect of 2,4‐dinitrophenol on the tissue concentration of iodine‐containing compounds in isotopically equilibrated intact rats

Escobar¹,

Rey²

1961

The Journal of Physiology

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that the administration of 2,4-dinitrophenol to mammals is accompanied by a sharp decrease of the plasma PBI without an increase of TSH secretion by the pituitary. (The following abbreviations are used: 2,4-dinitrophenol (DNP); thyroid-stimulating hormone (TSH); proteinbound iodine (PBI); trichloracetic acid precipitable (TCAp); thyroxinebinding globulin (TBG).) These findings are usually considered to be due to 'disruption' of the classical thyroid-pituitary feed-back mechanism. Goldberg et al. (1957) showed that the pituitaries of DNP-treated animals had not lost the ability of reacting to other stimuli, and concluded from their results that the data 'were not consistent with the simple classical feed-back theory of

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The Effect of Estrogens Upon the Peripheral Metabolism of Thyroxine *†

Cited by 87 publications

References 37 publications

The Effects of Noncalorigenic Congeners of Salicylate on the Peripheral Metabolism of Thyroxine*

The Effects of Noncalorigenic Congeners of Salicylate on the Peripheral Metabolism of Thyroxine*

Comparative study of serum ferritin levels after oral supplementation with ferrous sulphate and carbonyl iron in mild iron deficiency anemia in pregnancy

The effect of 2,4‐dinitrophenol on the tissue concentration of iodine‐containing compounds in isotopically equilibrated intact rats

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