Measurement of free thyroid hormones in patients on long-term phenytoin therapy

1984 ◽  
Vol 26 (5) ◽  
pp. 633-634 ◽  
Author(s):  
J. A. Franklyn ◽  
M. C. Sheppard ◽  
D. B. Ramsden
Keyword(s):  
Thyroid Hormones ◽  
Free Thyroid Hormones

Transient Prealbumin- Associated Hyperthyroxinemia in TSH-Producing Pituitary Adenoma

1990 ◽  
Vol 29 (01) ◽  
pp. 40-43 ◽  
Author(s):  
W. Langsteger ◽  
P. Költringer ◽  
P. Wakonig ◽  
B. Eber ◽  
M. Mokry ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Case Report ◽  
Pituitary Adenoma ◽  
Thyroid Hormones ◽  
Protein Binding ◽  
Alpha Subunit ◽  
Normal Range ◽  
Thyroxine Binding Globulin ◽  
Free Thyroid Hormones ◽  
Transmission Computed Tomography

This case report describes a 38-year-old male who was hospitalized for further clarification of clinically mild hyperthyroidism. His increased total hormone levels, the elevated free thyroid hormones and the elevated basal TSH with blunted response to TRH strongly suggested a pituitary adenoma with inappropriate TSH incretion. Transmission computed tomography showed an intrasellar expansion, 16 mm in diameter. The neoplastic TSH production was confirmed by an elevated alpha-subunit and a raised molar alpha-sub/ATSH ratio. However, T4 distribution on prealbumin (PA, TTR), albumin (A) and thyroxine binding globulin (TBG) showed a clearly increased binding to PA (39%), indicating additional prealbumin-associated hyperthyroxinemia. The absolute values of PA, A and TBG were within the normal range. After removal of the TSH-producing adenoma, basal TSH, the free thyroid hormones and T4 binding to prealbumin returned to normal. Therefore, the prealbumin-associated hyperthyroxinemia had to be interpreted as a transitory phenomenon related to secondary hyperthyroidism (T4 shift from thyroxine binding globulin to prealbumin) rather than a genetically conditioned anomaly of protein binding.

Effects of small doses of bovine TSH on serum levels of free and total thyroid hormones, their degradation products, and diiodotyrosine

1985 ◽  
Vol 108 (2) ◽  
pp. 211-216 ◽  
Author(s):  
G. Benker ◽  
C. Splittstößer ◽  
H. Meinhold ◽  
Th. Olbricht ◽  
D. Reinwein
Keyword(s):  
Thyroid Hormones ◽  
Degradation Products ◽  
Thyroid Volume ◽  
Serum Levels ◽  
Direct Stimulation ◽  
Absolute Increase ◽  
Free Thyroid Hormones ◽  
Measurable Parameter ◽  
Small Doses ◽  
Bovine Tsh

Abstract. Bovine TSH was administered iv to 10 normal volunteers in doses of 2.5, 7.5, 15 and 30 mU/kg. Brisk elevations of serum diiodotyrosine occurred already after the smallest dose (mean, + 183%) while larger doses had only slight additional effects. T3 rose much higher than T4 (+71% compared to +23% after 15 mU bTSH/kg), and free thyroid hormones exhibited changes similar to total T3 and total T4. The mean absolute increase in serum fT3 ranged from 2.03 to 9.04 pmol/l and proved to be an easily measurable parameter for the TSH effect. Dose-response effects were seen for the increases of fT4, fT3 and T3. TBG and rT3 did not change but the degradation product 3,3'-T2 showed large increments of serum levels. There was no correlation between the response of T3 and T4, fT3 and fT4, or diiodotyrosine and any of the other parameters of thyroid function. The interindividual differences in the magnitude of thyroid hormone response to TSH were considerable, and there was no relationship between this response and thyroid volume by ultrasound. We conclude that direct stimulation of the thyroid gland with bTSH in small doses leads to consistent increases of thyroid hormones, especially T3 and fT3, that the response varies between individuals, and that the precursor diiodotyrosine is released together with thyroid hormones.

scholarly journals Determinants of placental iodine concentrations in a mild-to-moderate iodine-deficient population: an ENVIRONAGE cohort study

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Kristof Y. Neven ◽  
Bianca Cox ◽  
Karen Vrijens ◽  
Michelle Plusquin ◽  
Harry A. Roels ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Biological Significance ◽  
Iodine Concentration ◽  
Stepwise Multiple Regression ◽  
Vitamin Supplementation ◽  
Winter Period ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Gestational Period

Abstract Background Iodine is an essential trace element for the production of thyroid hormones, and plays a key role during the gestational period for optimal foetal growth and (neuro-)development. To this day, iodine deficiency remains a global burden. Previous studies indicate that the placenta can store iodine in a concentration-dependent manner and serve as a long-term storage supply, but studies on the determinants of long-term placental iodine load are limited. Methods The placental iodine concentrations were determined for 462 mother-neonate pairs from the ENVIRONAGE birth cohort (Limburg, Belgium). Sociodemographic and clinical variables were obtained from questionnaires and medical files. Determinants of placental iodine concentration were identified using stepwise multiple regression procedures (p value < 0.15). The biological significance of our findings was investigated by measuring the plasma thyroid hormones in maternal and cord blood of 378 participants. Results A higher pre-pregnancy BMI, higher gestational weight gain, and alcohol consumption during pregnancy were linked with lower placental iodine storage. Multi-vitamin supplementation during pregnancy and longer gestation were associated with higher levels of placental iodine. Children born during the winter period had on average higher placental iodine levels. Besides, we found a significant positive time trend for placental iodine load over the study period 2013 to 2017. Lastly, we observed positive associations of both the maternal and cord plasma thyroxine concentrations with placental iodine load, emphasizing their biological link. Conclusions This study identified some determinants likely presenting a risk of reduced iodine storage during the gestational period of life. Future studies should elucidate the effects of lower placental iodine load on neonatal health, and health later in life.

Associations of Thyroid Hormones and Resting Heart Rate in Patients Referred to Coronary Angiography

2020 ◽  
Vol 52 (12) ◽  
pp. 850-855
Author(s):  
Eva Steinberger ◽  
Stefan Pilz ◽  
Christian Trummer ◽  
Verena Theiler-Schwetz ◽  
Markus Reichhartinger ◽  
...  
Keyword(s):  
Heart Rate ◽  
Coronary Angiography ◽  
Thyroid Hormones ◽  
Thyroid Stimulating Hormone ◽  
Resting Heart Rate ◽  
Free Triiodothyronine ◽  
Free Thyroid Hormones ◽  
Cardiovascular Morbidity And Mortality ◽  
Increased Risk ◽  
Significant Difference

AbstractResting heart rate (RHR) is associated with increased risk of cardiovascular morbidity and mortality. Thyroid hormones exert several effects on the cardiovascular system, but the relation between thyroid function and RHR remains to be further established. We evaluated whether measures of thyroid hormone status are associated with RHR in patients referred to coronary angiography. Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxin (FT4), and RHR were determined in 2795 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study. Median (25th to 75th percentile) serum concentrations were 1.25 (0.76–1.92) mU/l for TSH, 4.8 (4.2–5.3) pmol/l for FT3 and 17.1 (15.4-19.0) pmol/l for FT4, and mean (±standard deviation) RHR was 68.8 (±11.7) beats/min. Comparing the highest versus the lowest quartile, RHR (beats/min) was significantly higher in the fourth FT4 quartile [3.48, 95% confidence interval (CI): 2.23–4.73; p <0.001] and in the fourth FT3 quartile (2.30, 95% CI: 1.06–3.55; p <0.001), but there was no significant difference for TSH quartiles. In multiple linear regression analyses adjusting for various potential confounders, FT3 and FT4 were significant predictors of RHR (p <0.001 for both). In subgroups restricted to TSH, FT3, and FT4 values within the reference range, both FT3 and FT4 remained significant predictors of RHR (p <0.001 for all). In conclusion, in patients referred to coronary angiography, FT3 and FT4 but not TSH were positively associated with RHR. The relationship between free thyroid hormones and RHR warrants further investigations regarding its diagnostic and therapeutic implications.

scholarly journals Neonates Born to Mothers with Graves’ Disease: 15 Year Experience of a Pediatric Endocrinology Department

2020 ◽  
Vol 33 (7-8) ◽  
pp. 483
Author(s):  
Inês Romão Luz ◽  
João Rio Martins ◽  
Mónica Jerónimo ◽  
Joana Serra Caetano ◽  
Rita Cardoso ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Cord Blood ◽  
Thyroid Function ◽  
Case Series ◽  
Function Evaluation ◽  
Graves Disease ◽  
Thyrotropin Receptor ◽  
Second Trimester ◽  
Pediatric Endocrinology ◽  
Free Thyroid Hormones

Introduction: Graves disease is characterized by the existence of autoantibodies directed to the thyrotropin receptor, which can have a stimulatory/inhibitory action, in women with the condition, their fetus or neonate. Our aim was to review the case series of these neonates in order to establish neonatal thyroid function predictors.Material and Methods: Retrospective cohort study of the database of the Department of Pediatric Endocrinology, including patients born to mothers with Graves’ disease, between 2002 and 2017. Clinical and biochemical data were collected from mothers and offspring.Results: Fifty newborns, from 46 women with a median of 3.5 years after diagnosis, were included. During all trimesters of pregnancy, more than half of women had positive autoantibodies directed to the thyrotropin receptor. Not every woman had a complete thyroid function evaluation every trimester. In 32 newborns, cord blood screening was done. During the neonatal period, there were three cases of hypothyroidism and two of hyperthyroidism. The mothers of these five newborns had higher levels of free thyroid hormones during the second trimester (p = 0.03). The level of antibodies directed to the thyrotropin receptor was significantly higher in the cord blood (p = 0.03) and in the first neonatal test (p = 0.03) of these dysthyroid newborns.Discussion: Our results reinforce the need for every pregnant woman with Graves’ disease to be subject to thyroid function and autoantibodies evaluation during every trimester, as well as the importance of evaluating these antibodies in cord blood.Conclusion: High levels of free thyroid hormones during the second trimester of pregnancy and antibodies directed to the thyrotropin receptor value in cord blood are predictors of dysthyroidism in neonates born from women with Grave’s disease.

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