scholarly journals Is the Thyrotropin-Releasing Hormone Test Necessary in the Diagnosis of Central Hypothyroidism in Children

2003 ◽  
Vol 88 (12) ◽  
pp. 5696-5703 ◽  
Author(s):  
Ameeta Mehta ◽  
Peter C. Hindmarsh ◽  
Richard G. Stanhope ◽  
Caroline E. Brain ◽  
Michael A. Preece ◽  
...  
Keyword(s):  
Pituitary Hormone ◽  
Test Results ◽  
Trh Test ◽  
Free T4 ◽  
Central Hypothyroidism ◽  
Basal Serum ◽  
Serum T4 ◽  
The Mean ◽  
Test Increase ◽  
Serum Tsh

Abstract To determine the value of the TRH test, we analyzed the unstimulated serum T4 and TSH concentrations in 54 children with central hypothyroidism. A TRH test was performed in 30 patients. Midline brain defects (septo-optic dysplasia, 28; holoprosencephaly, 2) and combined pituitary hormone deficiencies were present in 30 and 52 patients, respectively. The mean serum free T4, total T4, and basal TSH concentrations were 0.6 ng/dl, 4.0 μg/dl, and 2.8 μU/ml, respectively. Five patients demonstrated elevated basal serum TSH concentrations. A normal TRH test [increase (Δ) in TSH, 4.5–17.8], based on data from 30 controls, was documented in 23.3% of patients. Brisk (ΔTSH, >17.8), absent/blunted (ΔTSH, <4.5), and delayed responses were documented in 16.7%, 30%, and 30% of patients, respectively. The mean age at diagnosis was 2.8 yr, with 8 patients evolving into TSH deficiency. It was not possible to differentiate patients as having pituitary or hypothalamic disease based solely on the TRH test results. Patients with septo-optic dysplasia were diagnosed earlier and had elevated basal serum TSH and PRL concentrations, diabetes insipidus, and evolving disease. Although full pituitary function assessment is mandatory to identify combined pituitary hormone deficiencies, a TRH test is not essential, and the diagnosis should be made by serial T4 measurements.

scholarly journals Measurement of Serum Free Thyroxine Index May Provide Additional Case Detection Compared to Free Thyroxine in the Diagnosis of Central Hypothyroidism

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Kevin M. Pantalone ◽  
Betul Hatipoglu ◽  
Manjula K. Gupta ◽  
Laurence Kennedy ◽  
Amir H. Hamrahian
Keyword(s):  
Elevated Serum ◽  
Free Thyroxine ◽  
Pituitary Hormone ◽  
Normal Range ◽  
Free T4 ◽  
Central Hypothyroidism ◽  
Serum Free ◽  
Free Thyroxine Index ◽  
Serum Tsh ◽  
Serum Free Thyroxine

The diagnosis of central hypothyroidism is often suspected in patients with hypothalamic/pituitary pathology, in the setting of low, normal, or even slightly elevated serum TSH and low free thyroxine (FT4). We present four cases of central hypothyroidism (three had known pituitary pathology) in whom central hypothyroidism was diagnosed after the serum free thyroxine index (FTI) was found to be low. All had normal range serum TSH and free thyroxine levels. This report illustrates that the assessment of the serum FTI may be helpful in making the diagnosis of central hypothyroidism in the appropriate clinical setting and when free T4 is in the low-normal range, particularly in patients with multiple anterior pituitary hormone deficiencies and/or with symptoms suggestive of hypothyroidism.

Human cold air habituation is independent of thyroxine and thyrotropin

1992 ◽  
Vol 72 (6) ◽  
pp. 2134-2139 ◽  
Author(s):  
R. L. Hesslink ◽  
M. M. D'Alesandro ◽  
D. W. Armstrong ◽  
H. L. Reed
Keyword(s):  
Single Daily Dose ◽  
Plasma Norepinephrine ◽  
Free T4 ◽  
Cold Air ◽  
Brown Adipose ◽  
Daily Dose ◽  
Before And After ◽  
Serum T4 ◽  
The Relationship ◽  
Serum Tsh

Thyroxine (T4) is required in species possessing brown adipose tissue (BAT) for the maintenance of cold tolerance and adaptation. In humans, who possess negligible quantities of BAT, the importance of T4 has not been demonstrated. We studied the effects of decreased serum T4 and thyrotropin (TSH) on human cold habituation after repeated cold air exposures. Eight men (T3+) received a single daily dose of triiodothyronine (T3; 30 micrograms/day), and another eight men (T3-) received a placebo. All 16 normal thyroid men underwent a standardized cold air test (SCAT) under basal conditions in January and again in March after eighty 30-min 4.4 degrees C air exposures (10/wk). Measurements of basal metabolic rate (BMR), O2 consumption (VO2), mean arterial pressure (MAP), plasma norepinephrine (NE), serum TSH, free and total T4, and free and total T3 were repeated before and after 8 wk of exposure. TSH, free T4, and total T4 were 50% lower for T3+ than for T3- subjects. Total and free T3 were not different between groups. BMR was unchanged after habituation, whereas the cold-stimulated VO2, MAP, and NE were significantly reduced for all subjects in March. The relationship between VO2 and NE (r2 = 0.44, P less than 0.001) during the initial SCAT was unchanged with habituation. We suggest that human cold habituation is independent of major changes in circulating T4 and TSH.

scholarly journals The Effect of Droloxifene and Estrogen on Thyroid Function in Postmenopausal Women1

2000 ◽  
Vol 85 (11) ◽  
pp. 4407-4410
Author(s):  
Ellen Marqusee ◽  
Lewis E. Braverman ◽  
Jennifer E. Lawrence ◽  
Judith S. Carroll ◽  
Ellen W. Seely
Keyword(s):  
Postmenopausal Women ◽  
Treatment Period ◽  
Thyroid Function ◽  
Free T4 ◽  
Double Blind ◽  
Stimulatory Action ◽  
Serum Free ◽  
Serum T4 ◽  
Conjugated Estrogen ◽  
Serum Tsh

Estrogen is known to increase serum T4-binding globulin (TBG) concentrations, thereby increasing serum total T4 concentrations. Serum free T4 concentrations, however, remain normal. Tamoxifen, a selective estrogen receptor modifier (SERM), also raises serum TBG concentrations, but whether newer SERMs with less stimulatory action on the endometrium do so is not known. We, therefore, compared the effect of droloxifene, a SERM, and conjugated equine estrogen on pituitary-thyroid function in normal postmenopausal women. Ten women were treated for 6 weeks with conjugated estrogen (Premarin), 0.625 mg/day, and droloxifene, 60 mg/day, in a double-blind crossover study with an intervening 4-week no-treatment period. We measured serum T4, T3, TBG, free T4 index, and TSH at baseline and at the end of each 6-week period. The baseline values were compared with the 6-week values using paired t tests. The mean (±sd) serum TBG concentrations increased significantly during both treatment periods (baseline, 1.5 ± 0.4 mg/dL; conjugated estrogens, 2.7 ± 0.6 mg/dL; droloxifene, 2.1 ± 0.6 mg/dL; P < 0.001 and P= 0.001, respectively). There were no significant changes in the serum free T4 index. Serum T4 and T3 concentrations increased during both treatment periods, however, the increase was significant only for T4 during the conjugated estrogen treatment period. The serum TSH concentrations increased significantly during both treatment periods (18% during conjugated estrogen and 11% during droloxifene), and the values remained within the normal range in all women. Administration of both conjugated estrogen and droloxifene for 6 weeks increases serum TSH and TBG concentrations, but does not alter free T4 index values in postmenopausal women.

Basal and TRH stimulated serum levels of TSH in patients with hyperprolactinaemia and in subjects on oestrogen treatment

1983 ◽  
Vol 102 (2) ◽  
pp. 173-178 ◽  
Author(s):  
Eva M. Erfurth ◽  
Pavo Hedner ◽  
Anders Nilsson
Keyword(s):  
Serum Level ◽  
Serum Levels ◽  
Plasma Prolactin ◽  
Thyroid Antibodies ◽  
Elevated Plasma ◽  
Oestrogen Treatment ◽  
Pituitary Dysfunction ◽  
Basal Serum ◽  
The Mean ◽  
Serum Tsh

Abstract. In 21 hyperprolactinaemic patients without other signs of pituitary dysfunction the mean basal serum level of TSH was 4.4 ± 0.47 μU/ml that was significantly (P < 0.001) higher than controls (2.5 ± 0.16 μU/ml and oestrogen treated individuals (2.4 ± 0.29 μU/ml). The TSH increase was more pronounced (P < 0.05) in hyperprolactinaemic patients without sellar enlargement and with moderately elevated plasma prolactin levels (155 ± 42 μg/ml) than in patients with sellar enlargement and higher plasma prolactin levels (857 ± 306 μg/ml). The serum levels of thyroxine and triiodothyronine in the hyperprolactinaemic patients did not differ significantly from controls. Patients with thyroid antibodies were excluded. The increased basal serum level of TSH in hyperprolactinaemia is compatible with the concept of a reduced dopaminergic tonus as the mechanism for both changes. In patients with advanced hyperprolactinaemia and sellar enlargement the high prolactin level may induce some inhibition of TSH release and explain their lower basal serum level of TSH that was probably not due to pituitary compression as they responded normally to TRH. The TSH response to TRH was significantly (P < 0.05) correlated to the basal serum TSH in all groups. The regression lines were very similar for hyperprolactinaemic patients and controls suggesting that in hyperprolactinaemia the thyrotroph has not changed its mode of response to TRH. In contrast, oestrogen treated subjects in addition to dependence on basal serum TSH levels showed a genuinely augmented response to TRH (164.6 ± 20.3%, P < 0.01) compared to controls.

scholarly journals The Effect of Perchlorate, Thiocyanate, and Nitrate on Thyroid Function in Workers Exposed to Perchlorate Long-Term

2005 ◽  
Vol 90 (2) ◽  
pp. 700-706 ◽  
Author(s):  
Lewis E. Braverman ◽  
XueMei He ◽  
Sam Pino ◽  
Mary Cross ◽  
Barbarajean Magnani ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Thyroid Volume ◽  
Production Plant ◽  
Sodium Iodide Symporter ◽  
Free T4 ◽  
High Exposure ◽  
Serum T4 ◽  
Serum Tsh ◽  
Serum And Urine

Perchlorate (ClO4−) and thiocyanate (SCN−) are potent and nitrate (NO3−) a weak competitive inhibitor of the thyroid sodium-iodide symporter. To determine the effects of long-term, high ClO4− exposure on thyroid function, we conducted a study of 29 workers employed for at least 1.7 yr (50% over 5.9 yr) in an ammonium ClO4− production plant in Utah. Serum ClO4−, SCN−, and NO3−; serum T4, free T4 index, total T3, thyroglobulin (Tg), and TSH; 14-h thyroid radioactive iodine uptake (RAIU); and urine iodine (I) and ClO4− were assessed after 3 d off (Pre) and during the last of three 12-h night shifts in the plant (During) and in 12 volunteers (C) not working in the plant. Serum and urine ClO4− were not detected in C; urine ClO4− was not detected in 12 of 29 and was 272 μg/liter in 17 Pre workers; serum ClO4− was not detected in 27 of 29 Pre; and serum and urine ClO4− were markedly elevated during ClO4− exposure to 868 μg/liter and 43 mg/g creatinine, respectively. Serum SCN− and NO3− concentrations were similar in all groups. Thyroid RAIUs were markedly decreased in During compared with Pre (13.5 vs. 21.5%; P &lt; 0.01, paired t) and were associated with an increase in urine I excretion (230 vs. 148 μg I/g Cr; P = 0.02, paired t) but were similar to those in the C group (14.4%). Serum TSH and Tg concentrations were normal and similar in the three groups. Serum T4 (8.3 vs. 7.7 μg/dl), free T4 index (2.4 vs. 2.2), and total T3 (147 vs. 134 ng/dl) were slightly but significantly increased in the During vs. Pre workers (P &lt; 0.01, paired t). Thyroid volumes and patterns by ultrasound were similar in the 29 workers and 12 community volunteers. In conclusion, high ClO4− absorption during three nights work exposure decreased the 14-h thyroid RAIU by 38% in ClO4− production workers compared with the RAIU after 3 d off. However, serum TSH and Tg concentrations and thyroid volume by ultrasound were not affected by ClO4−, suggesting that long-term, intermittent, high exposure to ClO4− does not induce hypothyroidism or goiter in adults.

EFFECT OF THYROTROPHIN RELEASING HORMONE (TRH) IN PATIENTS WITH PITUITARY DISORDERS

1977 ◽  
Vol 85 (3) ◽  
pp. 479-487 ◽  
Author(s):  
J. Lindholm ◽  
H. Dige-Petersen ◽  
L. Hummer ◽  
P. Rasmussen ◽  
O. Korsgaard
Keyword(s):  
Pituitary Tumour ◽  
Thyroid Stimulating Hormone ◽  
Trh Test ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Basal Serum ◽  
Chromophobe Adenoma ◽  
Before And After ◽  
Hypothyroid Patients ◽  
Serum Tsh

ABSTRACT The secretion and biological activity of thyroid stimulating hormone (TSH) were studied in 22 patients with a pituitary tumour (17 acromegalics and 5 patients with a chromophobe adenoma) and in 36 hypophysectomized patients (16 acromegalics and 20 with a chromophobe adenoma). Thyroid function was assessed by serum thyroxine (T4), serum triiodothyronine (T3), and thyroxine-binding globulin (TBG) concentration. Serum TSH was measured before and after injection of TSH releasing hormone (TRH), and in 19 hypophysectomized patients the T3 response after TRH was measured. In addition a TRH test was performed 1–2 weeks after surgery in 11 patients. The basal serum TSH did not differ from euthyroid control values in any of the groups and no late effect of hypophysectomy was observed. Subnormal peak TSH values were seen in 10 out of 37 euthyroid patients, whereas 9 out of 11 hypothyroid patients responded normally. Hypophysectomy caused an immediate but transient decrease in peak TSH in patients with a chromophobe adenoma only. The rise in serum T3 after TRH was significantly lower in hypophysectomized patients than in controls. An increase in TSH was followed by a T3 response in all patients except in 4 out of 8 euthyroid acromegalics. In patients operated on for a chromophobe adenoma the T3 response was correlated with serum T4, whereas this was not the case in acromegalics.

scholarly journals Age and the Thyrotropin Response to Hypothyroxinemia

2010 ◽  
Vol 95 (8) ◽  
pp. 3675-3683 ◽  
Author(s):  
Rebecca Over ◽  
Sonia Mannan ◽  
Hala Nsouli-Maktabi ◽  
Kenneth D. Burman ◽  
Jacqueline Jonklaas
Keyword(s):  
Age Groups ◽  
Primary Hypothyroidism ◽  
Age Group ◽  
Older Individuals ◽  
Free T4 ◽  
Pathological Alteration ◽  
The Mean ◽  
The Relationship ◽  
Two Populations ◽  
Serum Tsh

Context: Some studies suggest altered pituitary functioning and TSH production with aging. Objective: Our objective was to test the hypothesis that less TSH production occurs despite comparable hypothyroxinemia with advancing age. Design: We retrospectively studied adult outpatients of all ages with confirmed hypothyroidism and documented their TSH and free T4 concentrations. Participants: Two populations of 112 patients were subdivided into four age groups: 1) patients newly diagnosed with primary hypothyroidism and 2) thyroid cancer patients undergoing l-T4 withdrawal in preparation for diagnostic or therapeutic radioiodine. Main Outcome Measure: The relationship between paired free T4 and TSH concentrations and patient age was studied. Results: With spontaneous hypothyroidism, the mean TSH concentration decreased nonsignificantly in each ascending age group with comparable free T4 (FT4) concentrations (&lt;35 yr, 69 mIU/liter; 35–49 yr, 49 mIU/liter; 50–64 yr, 43 mIU/liter; &gt;64 yr, 29 mIU/liter). With iatrogenic hypothyroidism, the mean TSH concentration decreased significantly in each ascending age group (&lt;35 yr, 156 mIU/liter; 35–49 yr, 115 mIU/liter; 50–64 yr, 74 mIU/liter; &gt;64 yr, 46 mIU/liter; P &lt; 0.001) despite similar FT4 concentrations. The relationship between the log-transformed TSH and FT4 was significantly and inversely affected by age in multivariate analyses in both spontaneous hypothyroidism (P = 0.0005) and in iatrogenic hypothyroidism (P &lt; 0.0001). Conclusions: Age modifies the pituitary set point or response to comparably reduced free T4 concentrations, resulting in lesser serum TSH elevation in older individuals. This phenomenon occurs with both spontaneous and iatrogenic hypothyroidism. This may be an adaptive response in normal aging or a pathological alteration of pituitary function with age.

scholarly journals Levothyroxine Improves Abnormal Cardiac Bioenergetics in Subclinical Hypothyroidism: A Cardiac Magnetic Resonance Spectroscopic Study

2015 ◽  
Vol 100 (4) ◽  
pp. E607-E610 ◽  
Author(s):  
Asgar Madathil ◽  
Kieren G. Hollingsworth ◽  
Andrew M. Blamire ◽  
Salman Razvi ◽  
Julia L. Newton ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Subclinical Hypothyroidism ◽  
Fasting Glucose ◽  
Resonance Spectroscopy ◽  
Free T4 ◽  
Confounding Variables ◽  
The Mean ◽  
And Gender ◽  
Levothyroxine Treatment ◽  
Serum Tsh

Context: It is well established that subclinical hypothyroidism (SCH) is associated with mild cardiac dysfunction, but it is unknown whether there is an underlying impairment of cardiac bioenergetic function. Objective: The objective of the study was to quantify the cardiac phosphocreatine to adenosine triphosphate ratio (PCr to ATP) in SCH, compared with healthy controls, and to measure the effect of 6 months of levothyroxine treatment. Design and Setting: This was a 6-month, prospective, case-controlled interventional study. Participants and Main Outcome Measures: The PCr to ATP ratio was measured using phosphorus-31 magnetic resonance spectroscopy in subjects with SCH at baseline and after levothyroxine therapy (1.6 μg/kg·d) and compared with age- and gender-matched euthyroid controls. All subjects were free of overt heart disease. Results: Twenty-one subjects with SCH (normal free T4 and serum TSH between 4.1 and 10 mIU/L) and 17 controls were matched for age (mean age 40.5 vs 43.3 y) and sex (females 81% vs 82%) but differed in mean TSH (6.5 vs 2.1 mIU/L, P &lt; .001). At baseline the mean (±SD) PCr to ATP ratio in SCH was lower than in controls (1.80 ± 0.26 vs 2.07 ± 0.20, P = .001). In the 16 subjects studied after levothyroxine treatment, the PCr to ATP ratio improved (from 1.74 ± 0.24 to 1.91 ± 0.26, P = .004) and approached controls (borderline loss of significance, P = .051). On multivariate analysis, SCH was independently associated with a reduced PCr to ATP ratio, even after adjusting for confounding variables (body mass index and fasting glucose) (P = .001). Conclusion: Our results demonstrate early cardiac bioenergetic impairment in SCH, which is reversible with levothyroxine therapy. This mechanistic insight provides justification for longitudinal trials to determine whether improvement in bioenergetic function improves cardiovascular outcome.

Changes in pituitary and thyroid function with increasing age in young male rats.

1979 ◽  
Vol 237 (3) ◽  
pp. E224 ◽  
Author(s):  
F Azizi
Keyword(s):  
Thyroid Function ◽  
Subcutaneous Administration ◽  
Young Male ◽  
Thyroid Stimulating Hormone ◽  
Male Rats ◽  
Progressive Decline ◽  
Basal Serum ◽  
Serum T4 ◽  
Serum Tsh ◽  
Bovine Tsh

As the age of young adult male rats increased from 30 to 150 days, the serum thyroxine (T4) decreased by 50% and the serum thyroid-stimulating hormone (TSH) increased by 250%. There was no change in the serum triiodothyronine (T3). The increment in serum TSH after injection of thyrotropin-releasing hormone (TRH) was not significantly different at any of the ages studied, but the old animals had significantly lower increments in serum T4 and T3 after subcutaneous administration of bovine TSH. Despite a higher basal serum TSH, the older rats had a lesser increase in serum TSH after thyroidectomy or propylthiouracil. Thus, 1) there is a progressive decline in intrinsic thyroid function between 30 and 150 days of age in male rats, and 2) pituitary TSH response to fall in serum concentration of thyroid hormones is also decreased with age.

PITUITARY-THYROID FUNCTION IN SPIRONOLACTONE TREATED HYPERTENSIVE WOMEN

1979 ◽  
Vol 90 (3) ◽  
pp. 577-584 ◽  
Author(s):  
A. G. H. Smals ◽  
P. W. C. Kloppenborg ◽  
W. H. L. Hoefnagels ◽  
J. I. M. Drayer
Keyword(s):  
Thyroid Function ◽  
Bolus Injection ◽  
Serum Testosterone ◽  
High Dose ◽  
Enhancing Effect ◽  
Basal Serum ◽  
The Mean ◽  
17 Hydroxyprogesterone ◽  
Lh Rh ◽  
Serum Tsh

ABSTRACT Four weeks high dose spironolactone treatment (Aldactone® Searle, 100 mg q. i. d.) significantly enhanced the TSH (Δ max. 8.5 ± 4.1 vs. 4.6 ± 3.1 μU/ml, P < 0.05) and T3 (Δ max. 32±27 vs. 11 ± 16 ng/100 ml, P < 0.05) responses to an intravenous TRH/LH-RH bolus injection in 6 eumenorrhoeic euthyroid hypertensive women, without affecting basal serum TSH, T3 or T4 levels or the basal and stimulated LH, FSH and prolactin values (P > 0.10). The mean serum testosterone, 17-hydroxyprogesterone and oestradiol levels were also similar before and during therapy. Spironolactone, possibly by virtue of its antiandrogenic action, may exert its enhancing effect on pituitary-thyroid function by modulating the levels of receptors for TRH in the thyrotrophs or by altering the T3 receptor in the pituitary permitting a greater response to TRH.

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