Dual control of pituitary thyroid stimulating hormone secretion by thyroxine and triiodothyronine in athyreotic patients

Background: Patient responses to levothyroxine (LT4) monotherapy vary considerably. We sought to differentiate contributions of FT4 and FT3 in controlling pituitary thyroid stimulating hormone (TSH) secretion. Methods: We retrospectively assessed the relationships between TSH and thyroid hormones in 319 patients with thyroid carcinoma through 2914 visits on various LT4 doses during follow-up for 5.5 years (median, IQR 4.2, 6.9). We also associated patient complaints with the relationships. Results: Under varying dose requirements (median 1.84 µg/kg, IQR 1.62, 2.11), patients reached TSH targets below 0.4, 0.1 or 0.01 mIU/l at 73%, 54% and 27% of visits. While intercept, slope and fit of linearity of the relationships between lnTSH and FT4/FT3 varied between individuals, gender, age, LT4 dose and deiodinase activity influenced the relationships in the cohort (all p < 0.001). Deiodinase activity impaired by LT4 dose significantly affected the lnTSH–FT4 relationship. Dose increase and reduced conversion efficiency displaced FT3–TSH equilibria. In LT4-treated patients, FT4 and FT3 contributed on average 52% versus 38%, and by interaction 10% towards TSH suppression. Symptomatic presentations (11%) accompanied reduced FT3 concentrations (–0.23 pmol/l, p = 0.001) adjusted for gender, age and BMI, their relationships being shifted towards higher TSH values at comparable FT3/FT4 levels. Conclusions: Variation in deiodinase activity and resulting FT3 levels shape the TSH–FT4 relationship in LT4-treated athyreotic patients, suggesting cascade control of pituitary TSH production by the two hormones. Consequently, measurement of FT3 and calculation of conversion efficiency may identify patients with impaired biochemistry and a resulting lack of symptomatic control.

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Central TSH Dysregulation in a Patient with Familial Non-Autoimmune Autosomal Dominant Hyperthyroidism Due to a Novel Thyroid-Stimulating Hormone Receptor Disease-Causing Variant

Medicina ◽

10.3390/medicina57030196 ◽

2021 ◽

Vol 57 (3) ◽

pp. 196

Author(s):

Jasna Suput Omladic ◽

Maja Pajek ◽

Urh Groselj ◽

Katarina Trebusak Podkrajsek ◽

Magdalena Avbelj Stefanija ◽

...

Keyword(s):

Hormone Receptor ◽

Autosomal Dominant ◽

Signs And Symptoms ◽

Thyroid Stimulating Hormone ◽

Ablation Therapy ◽

Tsh Secretion ◽

Tshr Gene ◽

Adult Male Patient ◽

Stimulating Hormone

Background and Objectives. Familial non-autoimmune autosomal dominant hyperthyroidism (FNAH) is a rare cause of childhood hyperthyroidism. It is caused by the thyroid-stimulating hormone receptor (TSHR) gene variants. So far, only around 40 families with FNAH have been reported. Patients with activating TSHR variants demonstrated the same classical signs and symptoms of hyperthyroidism as seen in patients with Graves’ disease. Since 2012, ablative therapy is recommended to avoid relapses of hyperthyroidism and its consequences. Case Presentation. We presented a young adult male patient with a novel heterozygous TSHR disease-causing variant p.Arg418Lys (c.1253G>A) in the exon 10, who presented with a mild but progressive FNAH, with a follow-up since infancy. Discussion. Constantly suppressed TSH, including during the euthyreosis in childhood and hypothyreosis after iodine ablation therapy, suggested central dysregulation of the TSH secretion.

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Effects of trifluoperazine on rat prolactin, growth hormone, thyroid stimulating hormone and adrenocorticotrophin secretion in vitro

Acta Endocrinologica ◽

10.1530/acta.0.1030492 ◽

1983 ◽

Vol 103 (4) ◽

pp. 492-496 ◽

Cited By ~ 2

Author(s):

Ruth C. Powell ◽

Mark Daniels ◽

Graham K. Innes ◽

Michael J. Ashby ◽

Keith Mashiter

Keyword(s):

Growth Hormone ◽

Primary Cultures ◽

Hormone Secretion ◽

Thyroid Stimulating Hormone ◽

Pituitary Hormone ◽

Gh Secretion ◽

Tsh Secretion ◽

Stimulation Of ◽

Stimulating Hormone

Abstract. We have studied the effects of trifluoperazine, a proposed inhibitor of calmodulin directed cellular function, on adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH), prolactin (Prl) and growth hormone (GH) secretion from primary cultures of rat adenohypophyseal cells. 5 × 10−6 m and 10−5 m trifluoperazine caused a significant (P < 0.005) reversible dose-related decrease in basal Prl secretion but was less effective on basal GH secretion, significant reversible inhibition (P< 0.005) occurring only with 10−5 m. Trifluoperazine did not consistently alter basal ACTH or TSH secretion but did inhibit 10−2 m theophylline stimulation of ACTH, Prl and GH secretion and 1.5 × 10−7 m TRH stimulation of TSH and Prl secretion. Paradoxically 10−5 m trifluoperazine enhanced theophylline stimulation of TSH secretion. Our results show trifluoperazine to have differential effects on Prl, GH, ACTH and TSH secretion, which are consistent with the known calcium dependence of pituitary hormone secretion and may suggest a role for calmodulin in this process.

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Elevated thyroid-stimulating hormone is associated with poor sleep: a cross-sectional and longitudinal study

10.21203/rs.3.rs-391897/v1 ◽

2021 ◽

Author(s):

Yuerong Yan ◽

Jiaqi Li ◽

Huairong Tang ◽

Youjuan Wang ◽

Weiwei Zhang ◽

...

Keyword(s):

Sleep Quality ◽

Thyroid Stimulating Hormone ◽

Poor Sleep ◽

Subjective Sleep Quality ◽

Cross Sectional ◽

Tsh Secretion ◽

Quality Sleep ◽

Good Sleep ◽

Stimulating Hormone

Abstract Purpose Poor sleep and the accompanying TSH (Thyroid Stimulating Hormone) elevation are not uncommon since TSH secretion is controlled by the circadian rhythm. However, the true relationship between poor sleep and TSH elevation is unclear, and hence we aimed to elucidate this association by cross-sectional and longitudinal studies. Methods Participants with isolated elevated and normal TSH concentration were recruited, and the Pittsburgh Sleep Quality Index (PQSI) was used to assess sleep status. The patients with isolated TSH elevation were followed up longitudinally, and TSH levels were remeasured when sleep status improved. Results The proportion of poor sleep and occasional poor sleep among subjects with isolated TSH elevation was significantly higher than that in subjects with normal TSH (70.24% vs. 49.58%, p = 0.001; 9.52% vs. 1.68%, p = 0.006), and the ratio of good sleep was obviously decreased in subjects with isolated TSH elevation than normal TSH (20.24% vs. 48.74%, p < 0.001). Patients with isolated TSH elevation had significantly higher PSQI scores in the subjective sleep quality, sleep latency, sleep duration, and habitual sleep efficiency dimensions than subjects with normal TSH (all p < 0.05). In the follow-up study, among patients with isolated TSH elevation at baseline, the ratio of TSH normalization in patients who slept better was significantly higher than that in patients who still slept poorly (85.42% vs. 6.45%, p < 0.001). Conclusion This study revealed isolated elevated TSH concentrations tends to normalize when sleep status improves, and we recommend that clinicians inquire about sleep status thoroughly and reexamine thyroid hormone levels when sleep status improves.

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THYROID FUNCTION TESTS: A REVIEW

10.36106/ijsr/2502260 ◽

2021 ◽

pp. 73-76

Author(s):

Vasudev Sankhla ◽

Aman Deep

Keyword(s):

Thyroid Function ◽

Thyroid Dysfunction ◽

Radioactive Iodine ◽

Thyroid Stimulating Hormone ◽

Thyroid Function Tests ◽

Function Tests ◽

Tsh Secretion ◽

Line Test ◽

Radioactive Iodine Uptake

Thyroid function tests are one of the most common endocrine panels in general practice because a good understanding of when to order them, indications for treatment are important for the optimal treatment of thyroid dysfunction. Thyroid-stimulating hormone (TSH) should be the rst test to be performed on any patient with suspected thyroid dysfunction and in follow-up of individuals on treatment. It is useful as a rst-line test because even small changes in thyroid function are sufcient to cause a signicant increase in TSH secretion. Thyroxine levels may be assessed in a patient with hyperthyroidism, to determine the severity of hyperthyroxinemia. Antithyroid peroxidase measurements should be considered while evaluating patients with subclinical hypothyroidism and can facilitate the identication of autoimmune thyroiditis during the evaluation of nodular thyroid disease. The measurement of TSH receptor antibody must be considered when conrmation of Graves’ disease is needed and radioactive iodine uptake cannot be done.

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A raised thyroid stimulating hormone result - a 12-month follow-up study in general practice

Journal of Primary Health Care ◽

10.1071/hc10029 ◽

2010 ◽

Vol 2 (1) ◽

pp. 29 ◽

Cited By ~ 1

Author(s):

Veronique Gibbons ◽

John Conaglen ◽

Ross Lawrenson

Keyword(s):

General Practice ◽

Quantitative Research ◽

Best Practice ◽

Adult Population ◽

Laboratory Data ◽

Reference Interval ◽

Thyroid Stimulating Hormone ◽

Thyroid Function Tests ◽

Stimulating Hormone

INTRODUCTION: Subclinical hypothyroidism (SCH) is common in older patients. AIM: To review the management of patients identified with a raised thyroid stimulating hormone (TSH) result in a 12-month period and compare this to current guidelines from the New Zealand Best Practice Advocacy Centre (BPAC). METHODS: We collected laboratory data on thyroid function tests (TFTs) that were reported between December 2005 and November 2006 from two general practices with an adult population of approximately 21 000. Data were collected on symptoms, investigations, thyroid medication, family history and comorbidities. We used chi-squared tests to compare findings by age, gender and ethnicity. RESULTS: Older women of European descent were more likely to be to have initial results suggesting SCH. The number of follow-up tests ranged from 0 to 5 tests in a 12-month period. Forty-eight percent of individuals did not have any follow-up investigations. Seventy-three percent of FT4 tests taken are requested concurrently with TSH. Of those who had a repeat TSH test, just over 40% had a result within the reference interval. Twenty-eight percent had two TSH results consistent with SCH. Thirty-five percent of patients with antibody results were positive. The most commonly-recorded symptoms were tiredness and weight gain. DISCUSSION: We found inconsistencies in the management of SCH which were not related to patient characteristics such as age, gender or ethnicity. Further research is needed to determine if SCH is associated with increased morbidity and to provide a clear rationale for management of patients with SCH. KEYWORDS: Hypothyroidism; family practice; quantitative research; general practice

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