Determination of Triiodothyronine in Red Blood Cells by Radioimmunoassay

Ochi, Yukio; Hachiya, Takashi; Yoshimura, Manabu; Miyazaki, Tadayoshi; Majima, T; Kaimasu, Isao; Takahashi, Hakuo

doi:10.1507/endocrj1954.23.207

Cited by 8 publications

(5 citation statements)

References 4 publications

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“…The equilibrium partition coefficients measured in buffer suggest that the amount of erythrocyte-associated thyroid hormones may be 20 times (T 3 ) and 17 times (T 4 ) higher than the free concentration of hormones outside the cells. Erythrocyte-associated T 3 , therefore, represents about 20% of the total (free plus bound) T 3 in the serum, which is consistent with previous reports (7,9) indicating that the level of endogenous erythrocyte T 3 measured by RIA was 10-25% of the total plasma T 3 concentration. However, unlike the situation in rats (23), the kinetics of thyroid hormone exchange between erythrocytes and target tissues appear to be too slow to be physiologically important within the time of capillary transit.…”

Section: Discussionsupporting

confidence: 91%

“…(J Clin Endocrinol Metab 71: [1589][1590][1591][1592][1593][1594][1595]1990) H UMAN erythrocytes have been known to take up T 3 and T 4 in vitro for over 30 yr (3,4), and this uptake has been used as an index of the thyroid hormonebinding capacity of plasma proteins (5,6). More recently, interest has focussed on measuring the red cell content of T 3 or T 4 in various thyroid diseases (7)(8)(9).…”

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confidence: 99%

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Transport of Thyroid Hormones by Human Erythrocytes: Kinetic Characterization in Adults and Newborns*

Osty

Valensi

Samson

et al. 1990

The Journal of Clinical Endocrinology & Metabolism

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The uptake of [125I]T3 and [125I]T4 by human erythrocytes was studied. The erythrocytes were obtained from adult subjects (28-41 yr old) and suspended in a protein-free medium. The half-times of equilibration for both T3 and T4 were 6 min. At equilibrium, T3 was concentrated 55-fold inside the cells, while T4 was concentrated 40 times, but these accumulations were not dependent on either cellular ATP or the transmembrane Na+ gradient. The amounts of cell-associated thyroid hormones were 20 times (T3) and 17 times (T4) higher than the amounts of free extracellular hormones at 5 X 10(9) erythrocytes/mL (the blood concentration). Oligomycin and phloretin inhibited T3-saturable transport (but not T4 transport) independently of cellular energy. We suggest that thyroid hormones are concentrated by intracellular trapping. The rates of T3 and T4 efflux from preloaded erythrocytes were similar to the influx rates. The initial velocities of T3 (but not T4) uptake and efflux were 70% saturable. The uptake was specific because the unlabeled analogs T4, triiodothyroacetic acid, rT3, D-T3, and D,L-thyronine inhibited [125I]T3 uptake 60, 125, 160, 190, and 1600 times less, respectively, than did unlabeled T3. The kinetic parameters of T3-saturable uptake, Km, and maximum velocity were determined for three groups of subjects: newborns, 28 to 41-yr-old adults, and 76 to 90-yr-old adults. The Km (67 nmol/L in 28 to 41-yr-old adults) was not age dependent, BUT the maximum velocity was significantly higher in newborns than in adults. We conclude that T3 transport across the human erythrocyte membrane is mediated mainly by facilitated diffusion, whereas T4 transport results from free diffusion. Human erythrocytes might act as a circulating pool of thyroid hormones, especially T3 in newborns.

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Section: Discussionsupporting

confidence: 91%

mentioning

confidence: 99%

Transport of Thyroid Hormones by Human Erythrocytes: Kinetic Characterization in Adults and Newborns*

Osty

Valensi

Samson

et al. 1990

The Journal of Clinical Endocrinology & Metabolism

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“…Quantitative studies of RBC membrane uptake of iodothyronines and the relationship of membrane uptake to plas-ma protein-binding of thyroid hormones has been reported by others (Crispell and Coleman 1956;Hamolsky, Gobdetz and Freedberg 1959;Ochi, Hachiya, Yoshimura, Miyazaki, Majima, Kaimasu and Takahashi 1976), but previous reports have not analyzed the partition of hormone across the cell membrane.…”

Section: Discussionmentioning

confidence: 96%

Partition of Thyroid Hormone among Erythrocyte Cytosol, Erythrocyte Membrane and Human Plasma Binding Sites

Yoshida¹,

Pj²

1981

Horm Metab Res

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The partition of thyroid hormone among binding sites on plasma proteins, erythrocyte (RBC) membranes and cytoplasmic proteins has been examined in the context of recent direct estimates of intracellular RBC thyroid hormone content. Isotopic T3 and T4 uptakes by washed RBCs are identical (greater than 80% of tracer at 4 hr), but RBC binding when RBCs are suspended in plasma favors T3 (10% uptake vs. 2.5% for T4). The RBC cytosol: plasma T3 ratio is 1 : 21.

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“…The plasma-to-RBC ratio for T3 is reported as 3.2:1 [ 10 ] and the concentration of T4 in RBCs is 0.30–0.78 ng/mL, of which the mean value of 0.54 ng/mL was applied [ 11 ], accounting for less than 0.1% of the expected T4 concentration in the serum.…”

Section: Methodsmentioning

confidence: 99%

Development of an LC-HRMS/MS Method for Quantifying Steroids and Thyroid Hormones in Capillary Blood: A Potential Tool for Assessing Relative Energy Deficiency in Sport (RED-S)

Tuma,

Thomas,

Braun

et al. 2024

Metabolites

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Relative energy deficiency in sport (RED-S) is a condition that arises from persistent low energy availability (LEA), which affects the hypothalamic–pituitary axis and results in alterations of several hormones in both male and female athletes. As frequent blood hormone status determinations using venipuncture are rare in sports practice, microsampling offers promising possibilities for preventing and assessing RED-S. Therefore, this study aimed at developing a liquid chromatography–high-resolution tandem mass spectrometry (LC-HRMS/MS) method for quantifying relevant steroids and thyroid hormones in 30 μL of capillary blood obtained using Mitra® devices with volumetric absorptive microsampling technology (VAMS®). The results of the study showed that all validation criteria were met, including a storage stability of more than 28 days in a frozen state (−18 °C) and 14 days at room temperature (20 °C). The validated assay provided precise (<12%) and accurate (<13%) results for all the target analytes. Furthermore, as a proof of concept, autonomously collected VAMS® samples from 50 female and male, healthy, active adults were analyzed. The sensitivity of all analytes was adequate to quantify the decreased hormone concentrations in the RED-S state, as all authentic samples could be measured accordingly. These findings suggest that self-collected VAMS® samples offer a practical opportunity for regular hormone measurements in athletes and can be used for early RED-S assessment and progress monitoring during RED-S recovery.

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Determination of Triiodothyronine in Red Blood Cells by Radioimmunoassay

Cited by 8 publications

References 4 publications

Transport of Thyroid Hormones by Human Erythrocytes: Kinetic Characterization in Adults and Newborns*

Transport of Thyroid Hormones by Human Erythrocytes: Kinetic Characterization in Adults and Newborns*

Partition of Thyroid Hormone among Erythrocyte Cytosol, Erythrocyte Membrane and Human Plasma Binding Sites

Development of an LC-HRMS/MS Method for Quantifying Steroids and Thyroid Hormones in Capillary Blood: A Potential Tool for Assessing Relative Energy Deficiency in Sport (RED-S)

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