EFFECT OF PROLONGED ORAL ADMINISTRATION OF TRH ON PLASMA LEVELS OF THYROTROPHIN AND PROLACTIN IN NORMAL INDIVIDUALS AND IN PATIENTS WITH PRIMARY HYPOTHYROIDISM

1977 ◽  
Vol 85 (4) ◽  
pp. 744-752 ◽  
Author(s):  
Harald M. M. Frey ◽  
Egil Haug
Keyword(s):  
Elevated Serum ◽  
Primary Hypothyroidism ◽  
Trh Test ◽  
Normal Individuals ◽  
Term Administration ◽  
Maximal Rise ◽  
Trh Receptor ◽  
Serum Tsh ◽  
Tsh Levels

ABSTRACT Forty mg TRH/day was given orally for 3 weeks to 10 euthyroid women and 10 women with primary hypothyroidism on low replacement doses of thyroxine. Once weekly oral TRH was replaced by an iv TRH-test (0.4 mg) with measurement of serum concentration of TSH, prolactin (PRL), thyroxine (T4), triiodothyronine (T3) and cholesterol. In the normal group, mean serum T4 concentration increased after one week and remained elevated. Serum TSH concentration showed a slight tendency to decline. Maximal rise in TSH concentration after iv TRH (ΔTSH) fell from a mean of 4.0 ng/ml to 1.4 ng/ml within one week and stayed low. T3, cholesterol, PRL and ΔPRL were normal and unchanged throughout. In the hypothyroid group T4, T3, cholesterol, PRL and ΔPRL were not influenced by the TRH administration. In 2 patients (with the highest serum T4 concentrations) serum TSH concentration was normal and resistant to iv TRH. Of the 8 patients with elevated TSH, basal level and ΔTSH did not change in 2 (with subnormal T4 levels and the highest TSH levels). In the other 6 (with intermediate T4 levels) basal TSH fell from a mean of 10.1 ng/ml to 4.2 ng/ml, and ΔTSH from 10.0 ng/ml to 3.3 ng/ml after three weeks. It is concluded that in addition to feed-back effect of thyroid hormones, the pituitary response to long-term administration of TRH is determined by other factors. Among these may be reduced pituitary TRH receptor capacity and the activity of the TSH producing cells.

SERUM THYROTROPHIN AND THE RESPONSE TO THYROTROPHIN RELEASING HORMONE IN SYMPTOMLESS AUTOIMMUNE THYROIDITIS AND IN BORDERLINE AND OVERT HYPOTHYROIDISM

1974 ◽  
Vol 75 (2) ◽  
pp. 274-285 ◽  
Author(s):  
A. Gordin ◽  
P. Saarinen ◽  
R. Pelkonen ◽  
B.-A. Lamberg
Keyword(s):  
Autoimmune Thyroiditis ◽  
Elevated Serum ◽  
Mean Value ◽  
Primary Hypothyroidism ◽  
Overt Hypothyroidism ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
The Mean ◽  
The Individual ◽  
Serum Tsh

ABSTRACT Serum thyrotrophin (TSH) was determined by the double-antibody radioimmunoassay in 58 patients with primary hypothyroidism and was found to be elevated in all but 2 patients, one of whom had overt and one clinically borderline hypothyroidism. Six (29%) out of 21 subjects with symptomless autoimmune thyroiditis (SAT) had an elevated serum TSH level. There was little correlation between the severity of the disease and the serum TSH values in individual cases. However, the mean serum TSH value in overt hypothyroidism (93.4 μU/ml) was significantly higher than the mean value both in clinically borderline hypothyroidism (34.4 μU/ml) and in SAT (8.8 μU/ml). The response to the thyrotrophin-releasing hormone (TRH) was increased in all 39 patients with overt or borderline hypothyroidism and in 9 (43 %) of the 21 subjects with SAT. The individual TRH response in these two groups showed a marked overlap, but the mean response was significantly higher in overt (149.5 μU/ml) or clinically borderline hypothyroidism (99.9 μU/ml) than in SAT (35.3 μU/ml). Thus a normal basal TSH level in connection with a normal response to TRH excludes primary hypothyroidism, but nevertheless not all patients with elevated TSH values or increased responses to TRH are clinically hypothyroid.

scholarly journals Persistence of hyperprolactinemia after treatment of primary hypothyroidism and withdrawal of long term use of estrogen: are the tuberoinfundibular dopaminergic neurons permanently lesioned?

2005 ◽  
Vol 49 (3) ◽  
pp. 468-472 ◽  
Author(s):  
Luiz Augusto Casulari ◽  
Fábio Celotti ◽  
Luciana A. Naves ◽  
Lucília Domingues ◽  
Carla Papadia
Keyword(s):  
Dopaminergic Neurons ◽  
Hormone Replacement ◽  
Hormonal Contraceptive ◽  
Primary Hypothyroidism ◽  
Trh Test ◽  
Pituitary Mass ◽  
Thyroid Hormone Replacement ◽  
Before And After ◽  
High Doses

Long term use of high doses of estrogen and the presence of chronic hyperprolactinemia may, at least in the rat, provoke lesions in the tuberoinfundibular dopaminergic (TIDA) neurons responsible for the control of prolactin (Prl) secretion. This occurrence, which is not yet well documented in humans, may have taken place in a patient on chronic oral hormonal contraceptive (OC) treatment who was seen for primary hypothyroidism, hyperprolactinemia and a pituitary mass. After thyroid hormone replacement, OC withdrawn and bromocriptine treatment, this patient could not maintain normal Prl levels, unless continuously treated with a dopaminergic agonist even when MRI was indicative of a normal situation. Function of TIDA neurons was investigated by TRH test (200µg IV) performed before and after treatment with 25mg carbidopa plus 250mg L-dopa every 4 hours for one day. Basal TSH was normal (3.9µU/mL) whereas basal Prl was high (67.5 ng/mL); both TSH and Prl levels appropriately increased after TRH: peaks 31.8µU/mL and 157.8 ng/mL, respectively. After treatment with carbidopa/L-dopa, basal TSH (1.6µU/mL) and Prl (34ng/mL) decreased and the response to TRH was partially blocked (10.3µU/mL and 61ng/mL, respectively). In spite of a normal response, we discuss the possibility that the persistence of hyperprolactinemia is due to lesion of the TIDA neurons produced by the long term use of high doses of estrogens and by the presence of chronic hyperprolactinemia.

scholarly journals Low Serum TSH Levels and Negative TRH Test in Dialysis Patients

Nephron ◽  
1995 ◽  
Vol 71 (3) ◽  
pp. 357-358
Author(s):  
J. Evers ◽  
H. Scheid
Keyword(s):  
Dialysis Patients ◽  
Trh Test ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Low Serum

Endocrine involvement in children with β-thalassaemia major. Transverse and longitudinal studies. I. Pituitary-thyroidal axis function and its correlation with serum ferritin levels

1984 ◽  
Vol 107 (1) ◽  
pp. 49-53 ◽  
Author(s):  
L. Cavallo ◽  
D. Licci ◽  
A. Acquafredda ◽  
M. Marranzini ◽  
R. Beccasio ◽  
...  
Keyword(s):  
Longitudinal Studies ◽  
Thyroid Function ◽  
Serum Ferritin ◽  
Iron Chelation ◽  
Primary Hypothyroidism ◽  
Thalassaemia Major ◽  
Trh Test ◽  
Positive Correlations ◽  
Transversal Study ◽  
Tsh Levels

Abstract. Thyroid function was investigated by a TRH test in 24 clinically prepubertal children, 3–15 years old with β-thalassaemia major; in 7 of them the test was repeated once and in 2 twice at intervals of at least 12 months. Basal T4, T3, TBG and TSH levels and the TSH levels during a TRH test were determined and correlated with age and serum ferritin levels. Basal serum T4, T3 and TBG levels were lower and serum TSH levels were higher during the test and in the basal state in thalassaemia major children than in control children. These results show a compensated sub-clinical primary hypothyroidism. The transversal study did not show any significant correlation between the hormonal parameters studied and chronological age or serum ferritin levels. In contrast, the longitudinal study showed a significant correlation between pituitary-thyroidal axis function and siderosis (positive correlations between the variations of TSH levels as Δ, peak, 30 and 45 min values and the variations of serum ferritin levels). The thyroid impairment seems not to be correlated with serum ferritin levels in the transversal study because of the presence of an individual different sensitivity of the gland to the iron overload. The ferritin dependence of this impairment is shown only by longitudinal studies where individual differences in sensitivity of the gland are absent. Therefore iron chelation by desferrioxamine sc infusions, resulting in a decrease of ferritin, improves the deficient thyroid function.

Syndrome of'inappropriate secretion of thyroid-stimulating hormone' by partial target organ resistance to thyroid hormones

1981 ◽  
Vol 97 (3) ◽  
pp. 361-368 ◽  
Author(s):  
J. Salmerón De Diego ◽  
C. Alonso Rodriguez ◽  
A. Salazar Orlando ◽  
P. Sanchez Garcia Cervigon ◽  
E. Caviola Mutazzi ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Elevated Serum ◽  
Pituitary Tumour ◽  
Thyroid Stimulating Hormone ◽  
Target Organ ◽  
Resistance To Thyroid Hormones ◽  
Serum Thyroid Hormone ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Stimulating Hormone

Abstract. A 74 year old woman was found to have elevated serum thyroid-stimulating hormone (TSH) levels and elevated serum thyroid hormone levels, with clinical euthyroidism. There was no evidence of a pituitary tumour. TSH levels increased substantially during methimazole therapy. Administration of dexamethasone was followed by a prompt fall in serum TSH levels. Triiodothyronine (T3) was administered over a period of 20 days in doses from 25 μg to as much as 100 μg daily causing a rise in serum T3 above 700 ng/100 ml, a decline of T4 and a blunting of the response to thyrotrophinreleasing hormone (TRH), with normal metabolic responses (pulse rate, photomotogram, cholesterol). These results suggest that the patient's disorder is due to partial target organ resistance to thyroid hormones.

Hypothyroidism following Treatment for Head and Neck Cancer

1981 ◽  
Vol 90 (5) ◽  
pp. 449-453 ◽  
Author(s):  
Donald P. Vrabec ◽  
Timothy J. Heffron
Keyword(s):  
Radiation Therapy ◽  
Head And Neck ◽  
Thyroid Function ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Primary Hypothyroidism ◽  
Overt Hypothyroidism ◽  
Patient Will ◽  
Effects Of Radiation ◽  
Tsh Levels

One hundred ninety-six head and neck patients were studied to determine the effects of radiation therapy and surgery on thyroid function. Serum thyroid-stimulating hormone (TSH) levels were obtained as a screening test for primary hypothyroidism. Elevated TSH levels were found in 57 of the 196 patients (29.1%). The highest incidence of abnormal TSH values (66%) occurred in the group treated with combination radiation therapy and surgery, including partial thyroidectomy. TSH levels rose early in the posttreatment period with 60% of the abnormal values occurring within the first three posttreatment years. Posttreatment thyroid dysfunction was twice as common in women (48.6%) as in men (25.4%). When serum thyroxine levels by radioimmunoassay (T4RIA) were correlated with the elevated serum TSH levels, a similar pattern was seen with 65% of the patients in Group 3 having a decreased T4RIA level indicating overt hypothyroidism. Pretreatment levels of thyroid function including thyroid antibody studies should be established for all patients. Serial TSH levels should be done every three months during the first three posttreatment years and semiannually thereafter as long as the patient will return for follow-up care. All patients treated with combination radiation therapy and surgery who develop elevated TSH levels should be treated with thyroid replacement therapy. Patients receiving radiation therapy alone should receive replacement thyroid therapy if they develop a depressed T4RIA value or a pattern of gradually increasing TSH levels.

A study of thyroid function after subtotal thyroidectomy for Graves' disease: particularly on TRH tests, T3 suppression tests and antithyroid antibodies in euthyroid patients

1983 ◽  
Vol 103 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Osamu Fukino ◽  
Hajime Tamai ◽  
Shinichi Fujii ◽  
Noriyuki Ohsako ◽  
Sunao Matsubayashi ◽  
...  
Keyword(s):  
Elevated Serum ◽  
Subtotal Thyroidectomy ◽  
Graves Disease ◽  
Trh Test ◽  
Antithyroid Antibodies ◽  
Abnormal Response ◽  
Suppression Test ◽  
Recurrent Hyperthyroidism ◽  
Serum Tsh

Abstract. Of 305 patients who underwent subtotal thyroidectomy for Graves' disease between 1969 and 1975, recurrent hyperthyroidism was found in 31 (10.2%) and hypothyroidism in 18 (5.9%). The remaining 256 patients were clinically euthyroid, but an elevated serum TSH level was found in 104 (34.1%) and an elevated serum T3 level in 19 (6.28%). In 57 of 133 clinically and biochemically euthyroid patients, a TRH test, T3 suppression test and measurement of antithyroid antibodies were performed. Twenty-nine of the 57 patients (50.9%) showed an abnormal response to TRH. Eight of these (14.0%) showed an impaired or absent response. The T3 suppression test showed that 15 of the 57 patients (26.3%) were non-suppressible. Positive antithyroid antibodies, especially antimicrosomal antibodies, were more frequent in non-suppressible and TRH-non-responsive patients than in suppressible and TRH-responsive patients. It is suggested that after operation for Graves' disease: 1) only half of the clinically euthyroid patients were biochemically euthyroid, 2) of the clinically and biochemically euthyroid patients, there were many with abnormalities in TRH responsiveness and T3 suppressibility, and 3) thyroid functional status is unstable and long careful follow-up is important after operation for Graves' disease.

Factors Predicting Hypothyroidism in Long-Term Follow-Up after131I Therapy

1988 ◽  
Vol 27 (04) ◽  
pp. 135-139 ◽  
Author(s):  
M. Critchley ◽  
C. R. Squire ◽  
T. M. D. Gimlette
Keyword(s):  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Elevated Serum ◽  
Thyroid Autoantibodies ◽  
Radioiodine Treatment ◽  
Long Term Follow Up ◽  
Serum Tsh

187 patients, euthyroid for more than a year after radioiodine treatment for hyperthyroidism, were studied for 10 years; 81 (43%) became hypothyroid. The incidence of hypothyroidism was lower in patients initially presenting with large thyroids (28%) or with nodular thyroids (22%) and in those without thyroid autoantibodies (31 %). During follow-up, an elevated serum TSH was present in all 81 patients when they became hypothyroid (sensitivity and negative predictive value 100%), and was present for at least a year in 98% of these. However, an elevated serum TSH was also present in 48% of 106 patients remaining euthyroid (positive predictive value 61 %). FT4I was low in 94% of patients who became hypothyroid and normal in 80% of patients who remained euthyroid (positive predictive value 78%, negative predictive value 93%). Serum TSH and FT4I were the best biochemical predictors. FT3I and serum cholesterol were less satisfactory. A palpable thyroid becoming impalpable, though readily assessed, was limited in usefulness. Clinical appraisal remains important and a progressive, though perhaps less rapid, later increase in the incidence of hypothyroidism appears likely.

Suppression of Elevated Serum TSH Levels in Hypothyroidism by Fusaric Acid

1977 ◽  
Vol 45 (1) ◽  
pp. 95-98 ◽  
Author(s):  
MANABLf YOSHIMURA ◽  
TAKASHI HACHIYA ◽  
YUKIO OCHI ◽  
AKIO NAGASAKA ◽  
AKIO TAKEDA ◽  
...  
Keyword(s):  
Fusaric Acid ◽  
Elevated Serum ◽  
Serum Tsh ◽  
Tsh Levels

Influence of dopaminergic inhibition on serum levels of thyrotrophin and prolactin in patients with hypothyroidism before and after prolonged oral administration of TRH

1983 ◽  
Vol 104 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Harald M. M. Frey ◽  
Egil Haug
Keyword(s):  
Oral Administration ◽  
Serum Levels ◽  
Primary Hypothyroidism ◽  
Dopamine Antagonist ◽  
Trh Stimulation ◽  
Before And After ◽  
The Mean ◽  
Pre Treatment ◽  
Serum Tsh

Abstract. Forty mg TRH/day given orally for 3 weeks to 8 patients with mild primary hypothyroidism decreased serum TSH from a mean of 4.0 ng/ml ± 1.2 (se) to 2.0 ng/ml ± 0.4 (49%), and their mean incremental TSH response to iv TRH was equally reduced from 8.6 ng/ml ± 2.5 to 4.0 ng/ml ± 1.9 (46%). In the same patients serum Prl was 8.2 ng/ml ± 2.2 before oral TRH treatment and 6.6 ng/ml ± 1.5 (81%) after treatment, and the mean incremetal Prl response to iv TRH was reduced from 43.5 ng/ml ± 5.0 to 35.9 ng/ml ± 7.5(83%). The oral administration of 10 mg of the dopamine antagonist metoclopramide increased mean serum TSH from 0.6 ng/ml ± 0.1 (se) to 0.7 ng/ml ± 0.1 (120%) in euthyroid subjects and from 4.0 ng/ml ±1.2 to 5.7 ng/ml ± 1.6 (145%) in patients with primary hypothyroidism, and mean serum Prl from 8.6 ng/ml ± 0.8 to 109.5 ng/ml ± 24.3 (1251%) and from 8.2 ng/ml ± 2.2 to 119.6 ng/ml ± 45.5(1460%), respectively. The incremental TSH responses to iv TRH increased 2.3-fold in euthyroid subjects pre-treated with metoclopramide, while no change was observed in the TSH responsiveness in patients with primary hypothyroidism following metoclopramide pre-treatment. In the euthyroid subjects metoclopramide treatment had no effect on the Prl response to iv TRH. In the primary hypothyroid group metoclopramide pre-treatment caused a reduced Prl response to iv TRH in more than 50% of the patients. It is concluded that long-term TRH treatment decreased the serum levels of TSH and Prl as well as the incremental increases in TSH and Prl to iv TRH stimulation in patients with primary hypothyroidism. Long-term TRH treatment did not change the TSH and Prl responses to the dopamine antagonist metoclopramide.

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