A Radioimmunoassay of Thyroxine

Chopra, Indie J.; Solomon, David H.; Ho, R. Sherry

doi:10.1210/jcem-33-5-865

Cited by 111 publications

(39 citation statements)

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“…Thyroid glands were homogenized, and an aliquot hydrolyzed with Pronase (Calbiochem, La Jolla, Calif.) under previously described conditions (17,18). The hydrolysates were extracted with 2 volumes of 95% ethanol and rT3, T3, and T4 were determined by radioimmunoassays as described previously (1,18,19). RESULTS…”

Section: Methodsmentioning

confidence: 99%

An assessment of daily production and significance of thyroidal secretion of 3, 3', 5'-triiodothyronine (reverse T3) in man.

Chopra¹

1976

J. Clin. Invest.

303

111

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A B S T R A C T While 3,3',5'-triiodothyronine (reverse TS, rTs) has been detected both in human serum and in thyroglobulin, no quantitative assessment of its metabolic clearance rate (MCR), production rate (PR), or secretion by the thyroid is yet available. This study examines this information in euthyroid subjects and evaluates it in light of similar information about two other iodothyronines in the thyroid: 3,5,3'-triiodothyronine (Ta) and thyroxine (T4). Thus, it was noted that rTs is cleared from human serum at a much faster rate than are Ts and T4; the mean (±-SE) MCR of rT3 was 76.7±5.4 liters/day in 10 subjects, whereas MCR-T3 and MCR-T4 in 8 of them were 26.0±2.2 liters/day and 1.02±0.06 liters/day, respectively. Therefore, even though the mean serum concentration of rT3, 48+2.8 ng/ 100 ml, was much lower than that (128±6.7 ng/100 ml) of T3, the mean PR-rTs (36.5+2.8 ,ug/day) and the mean PR-T3 (33.5±3.7 Ag/day) were similar; in comparison, the mean serum concentration and PR of T4 were 8.6± 0.5 ,ug/100 ml and 87.0±3.9 Mg/day, respectively. These data and those on the relative proportion of rT3, T3, and Ts in 10 thyroid glands were used to assess the significance of the contribution of thyroidal secretion to PRrTs and PR-Ta. It was estimated that whereas thyroidal secretion may account for about 23.8% of serum T3 (or PR-Ta), it may account for only about 2.5% of serum rTa (or PR-rTs). Since peripheral metabolism of T4 is the only known source of rT3 and Ta other than the thyroidal secretion, it could be calculated that as much as 73.0 Ag or 84% of daily PR-T4 may normally be metabolized by monodeiodination either to T3 or to rT3.MCR and PR of various iodothyronines were also examined in five cases with hepatic cirrhosis, where, as documented previously, serum rT3 may be elevated while Received for publication 2 September 1975 and in revised form 20 February 1976. serum Ta is diminished. The mean MCR-rT3 in these cases (41.0 liters/day) was clearly (P < 0.005) less than that (76.7 liters/day) in normal subjects. This was the case at a time when the mean MCR-Ta (26.7 liters/day) and the mean MCR-T4 (1.19 liters/day) did not differ from those (vide supra) in normal subjects. Distinct from changes in MCRs, the mean PR-rT3 (33.0 Ag/day) was similar to, and the mean PR-T3 (10.1 ug/day) and the mean PR-T4 (66.4 Mg/day) were much less than, the corresponding value in normal subjects. Furthermore, while the ratio of PR-rT3 and PR-T4 (rT3/T4) in individual patients was either supranormal or normal, the ratio of PR-Ta and PR-T4 (T3/T&) was clearly subnormal. The various data suggest that: (a) just as in the case of T3, the thyroid gland is a relatively minor source of rT3; peripheral metabolism of T4 is apparently its major source; (b) the bulk of T4 metabolized daily is monodeiodinated to T3 or to rT3; (c) monodeiodination may be an obligatory step in metabolism of T4; (d) monodeiodination of T4 to rTa is maintained normal or is increased in hepatic cirrhosis at a time when monodeiodination of T4 to Ta is decr...

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Section: Methodsmentioning

confidence: 99%

An assessment of daily production and significance of thyroidal secretion of 3, 3', 5'-triiodothyronine (reverse T3) in man.

Chopra¹

1976

J. Clin. Invest.

303

111

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“…9 The analytical sensitivity for T3 and T4 assays was 0.04 ng/mL and 0.4 µg/dL respectively. For TSH we followed 1 hour incubation procedure for which analytical sensitivity was 0.078 µIU/mL.…”

Section: Laboratory Methodsmentioning

confidence: 94%

Thyroid Function Status in Indian Adult Nonpregnant Females in Ranchi, India

Hazra¹,

Singh²,

Mitra³

et al. 2017

Indian Journal of Medical Biochemistry

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“…10,11 The analytical sensitivities for T3, T4, and TSH assays were 0.04 ng/mL, 0.4 µg/dL, and 0.078 µIU/mL (1 hour incubation procedure) respectively. The inter-and intra-assay reproducibility values for T3 assays were 8.9% (for low serum range) and <5.5% and <7% (for high serum range).…”

Section: Laboratory Hormonal Analysismentioning

confidence: 99%

Specific Reference Intervals of Serum Triiodothyronine, Thyroxine, and Thyroid-stimulating Hormone in Normal Pregnant Indian Women as per Trimester

Hazra¹,

Mitra²,

Pal³

2017

Indian Journal of Medical Biochemistry

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Aim Maternal thyroid hormone levels during pregnancy are vital for the health of the mother as well as the developing child. Fetal growth is affected by maternal thyroid levels. Various physiological changes like alterations of thyroxine-binding globulins, human chorionic gonadotropin level, and changes in iodide metabolism affect maternal thyroid hormone levels. Therefore, reference intervals (RIs) for thyroid hormones in pregnant population require to be established separately from the general population. Materials and methods The RIs of serum triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) were determined in healthy pregnant women by enzyme-linked immunosorbent assay (ELISA) technique after segregating them into three trimesters. This study was conducted in a 492-bedded zonal-level hospital. The reference population was chosen from a study population of pregnant women by strict inclusion and exclusion criteria. The assays were done by the most-commonly used, economical ELISA method employing standard kits. Tests were done using accurate and precise methods with proper quality control measures. Results The RIs were calculated from the central 95% of distribution of total T3, total T4, and TSH values located between 2.5 and 97.5 percentile values. The 0.90 confidence intervals for the upper and lower reference limits were calculated. The values thus obtained were different from those provided by the manufacturer kit literature. Conclusion It is recommended to determine one's own laboratory-specific, method-specific, trimester-wise RIs for maternal thyroid hormone status and use them for screening of pregnant women. How to cite this article Chakrabarty BK, Mitra B, Pal R, Hazra N. Specific Reference Intervals of Serum Triiodothyronine, Thyroxine, and Thyroid-stimulating Hormone in Normal Pregnant Indian Women as per Trimester. Indian J Med Biochem 2017;21(1):17-21.

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A Radioimmunoassay of Thyroxine

Cited by 111 publications

References 0 publications

An assessment of daily production and significance of thyroidal secretion of 3, 3', 5'-triiodothyronine (reverse T3) in man.

An assessment of daily production and significance of thyroidal secretion of 3, 3', 5'-triiodothyronine (reverse T3) in man.

Thyroid Function Status in Indian Adult Nonpregnant Females in Ranchi, India

Specific Reference Intervals of Serum Triiodothyronine, Thyroxine, and Thyroid-stimulating Hormone in Normal Pregnant Indian Women as per Trimester

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