Quantification of thyroid hormones via online-SPE-LC-MS/MS from different biological matrices

Little is known about the kinetics and metabolism of thyroid hormones in the hypothyroid state. To investigate these factors, we developed a reliable method for measurement of serum thyroxine (T4), triiodothyronine (T3), reverse-T3 (rT3) and stable isotope-labeled T4 ([13C9]T4), using online solid-phase extraction liquid chromatography–mass spectrometry/mass spectrometry (online SPE LC–MS/MS). We measured supply and turnover rates of T4 in thyroidectomized (Tx) rats using [13C9]T4 as a tracer. In rats, serum T4, T3 and rT3 were decreased but not completely ablated after surgical Tx. Endogenous T4 and T3 levels in Tx rats were maintained at a constant low level throughout the experimental period. [13C9]T4 levels declined with a half-life of ∼1.2 days after it was administered to Tx rats intravenously. These findings strongly suggest that serum T4 levels in Tx rats are maintained by T4 supplied by extra-thyroidal tissues (e.g. secretion of extra-thyroidal storage, enhancement of enterohepatic recirculation, and production in extra-thyroidal tissues). Moreover, the turnover rate of T4 in Tx rats was approximately twofold lower than in controls. This finding suggests that degradation of serum T4 is repressed by Tx. In conclusion, serum T4 is maintained at a constant low level by T4 supply from extra-thyroidal tissues and repression of T4 degradation in Tx rats. The powerful online SPE LC–MS/MS tool can be used to investigate thyroid hormones kinetics and metabolism, and thus has the potential to be used as a diagnostic tool and to investigate the pathogenesis of thyroid disease.

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Abstract #1180: Trimester Specific Reference Interval for Thyroid Hormones During Pregnancy at a Tertiary Care Hospital in Haryana, India.

Endocrine Practice ◽

10.1016/s1530-891x(20)44828-1 ◽

2016 ◽

Vol 22 ◽

pp. 293

Author(s):

Rajesh Rajput ◽

Bhagat Singh ◽

Vasudha Goel ◽

Amit Verma ◽

Shashi Seth ◽

...

Keyword(s):

Thyroid Hormones ◽

Tertiary Care Hospital ◽

Tertiary Care ◽

Reference Interval ◽

Specific Reference ◽

Care Hospital

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259 Thyroid hormones in chronic heart failure outpatients

European Journal of Heart Failure Supplements ◽

10.1016/s1567-4215(06)80161-x ◽

2006 ◽

Vol 5 (1) ◽

pp. 56-56

Author(s):

A BARISON ◽

L RONDININI ◽

S GUIDERI ◽

M COCEANI ◽

M SCARLATTINI ◽

...

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Thyroid Hormones

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The Role of Zinc in Thyroid Hormones Metabolism

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000262 ◽

2019 ◽

Vol 89 (1-2) ◽

pp. 80-88 ◽

Cited By ~ 6

Author(s):

Juliana Soares Severo ◽

Jennifer Beatriz Silva Morais ◽

Taynáh Emannuelle Coelho de Freitas ◽

Ana Letícia Pereira Andrade ◽

Mayara Monte Feitosa ◽

...

Keyword(s):

Thyroid Hormones ◽

Scientific Evidence ◽

Thyroid Stimulating Hormone ◽

Zinc Transporters ◽

Serum Concentrations ◽

Metabolic Adaptations ◽

Serum T3 ◽

Regulatory Effects ◽

Shed Light

Abstract. Thyroid hormones play an important role in body homeostasis by facilitating metabolism of lipids and glucose, regulating metabolic adaptations, responding to changes in energy intake, and controlling thermogenesis. Proper metabolism and action of these hormones requires the participation of various nutrients. Among them is zinc, whose interaction with thyroid hormones is complex. It is known to regulate both the synthesis and mechanism of action of these hormones. In the present review, we aim to shed light on the regulatory effects of zinc on thyroid hormones. Scientific evidence shows that zinc plays a key role in the metabolism of thyroid hormones, specifically by regulating deiodinases enzymes activity, thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) synthesis, as well as by modulating the structures of essential transcription factors involved in the synthesis of thyroid hormones. Serum concentrations of zinc also appear to influence the levels of serum T3, T4 and TSH. In addition, studies have shown that Zinc transporters (ZnTs) are present in the hypothalamus, pituitary and thyroid, but their functions remain unknown. Therefore, it is important to further investigate the roles of zinc in regulation of thyroid hormones metabolism, and their importance in the treatment of several diseases associated with thyroid gland dysfunction.

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Effects of Maternal Flaxseed Supplementation on Female Offspring of Diabetic Rats in Serum Concentration of Glucose, Insulin, and Thyroid Hormones

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000259 ◽

2019 ◽

Vol 89 (1-2) ◽

pp. 45-54

Author(s):

Akemi Suzuki ◽

André Manoel Correia-Santos ◽

Gabriela Câmara Vicente ◽

Luiz Guillermo Coca Velarde ◽

Gilson Teles Boaventura

Keyword(s):

Thyroid Hormones ◽

High Fat Diet ◽

Female Offspring ◽

Flaxseed Oil ◽

Diabetic Rats ◽

High Fat ◽

Glucose Levels ◽

Blood Glucose Levels ◽

Flaxseed Flour ◽

Maternal Consumption

Abstract. Objective: This study aimed to evaluate the effect of maternal consumption of flaxseed flour and oil on serum concentrations of glucose, insulin, and thyroid hormones of the adult female offspring of diabetic rats. Methods: Wistar rats were induced to diabetes by a high-fat diet (60%) and streptozotocin (35 mg/kg). Rats were mated and once pregnancy was confirmed, were divided into the following groups: Control Group (CG): casein-based diet; High-fat Group (HG): high-fat diet (49%); High-fat Flaxseed Group (HFG): high-fat diet supplemented with 25% flaxseed flour; High-fat Flaxseed Oil group (HOG): high-fat diet, where soya oil was replaced with flaxseed oil. After weaning, female pups (n = 6) from each group were separated, received a commercial rat diet and were sacrificed after 180 days. Serum insulin concentrations were determined by ELISA, the levels of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) were determined by chemiluminescence. Results: There was a significant reduction in body weight at weaning in HG (−31%), HFG (−33%) and HOG (44%) compared to CG (p = 0.002), which became similar by the end of 180 days. Blood glucose levels were reduced in HFG (−10%, p = 0.044) when compared to CG, and there was no significant difference between groups in relation to insulin, T3, T4, and TSH after 180 days. Conclusions: Maternal severe hyperglycemia during pregnancy and lactation resulted in a microsomal offspring. Maternal consumption of flaxseed reduces blood glucose levels in adult offspring without significant effects on insulin levels and thyroid hormones.

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Transient Prealbumin- Associated Hyperthyroxinemia in TSH-Producing Pituitary Adenoma

Nuklearmedizin ◽

10.1055/s-0038-1629511 ◽

1990 ◽

Vol 29 (01) ◽

pp. 40-43 ◽

Cited By ~ 3

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.

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