TRH (Thyroid-Releasing Hormone) Tests

1984 ◽  
Vol 6 (6) ◽  
pp. 189-190
Keyword(s):  
Binding Proteins ◽  
Elevated Serum ◽  
Graves Disease ◽  
Base Line ◽  
Trh Test ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Free Thyroxine Index ◽  
Serum T4 ◽  
Line Test

I have read with great interest "Goiter in Children" by Foley (PIR 1984;5:259). The author stated: "In patients with thyromegaly and mild symptoms of hyperthyroidism, a TRH test will help to discriminate hyperthyroxemia secondary to increased or abnormal serum thyroxine binding proteins from early Graves disease, factitious hyperthyroidism, toxic thyroiditis, and TSH-mediated hyperthyroidism." I would suggest the use of a triiodothyronine (T3) resin uptake as a base-line test. An elevated serum thyroxine (T4) value in conjunction with a diminished T3 resin uptake suggests thyroxine-binding globulin (TBG) excess, which can be confirmed by specific quantitation of TBG. Patients with familial dysalbuminemic hyperthyroxinemia (FDH) have elevated levels of serum T4 and free thyroxine index (FT4l) values but normal T3 resin uptake and TBG levels.

Graves’ Disease Associated with Elevated Serum Thyroxine-Binding Globulin Concentrations*

1980 ◽  
Vol 51 (2) ◽  
pp. 325-329 ◽  
Author(s):  
YUKIKO YABU ◽  
NOBUYUKI AMINO ◽  
KIYOMI NAKATANI ◽  
KIYOSHI ICHIHARA ◽  
MIZUO AZUKIZAWA ◽  
...  
Keyword(s):  
Elevated Serum ◽  
Graves Disease ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine

ENDOCRINE CHANGES BEFORE AND AFTER THE MENARCHE

1973 ◽  
Vol 74 (4) ◽  
pp. 685-694 ◽  
Author(s):  
B.-A. Lamberg ◽  
R.-L. Kantero ◽  
P. Saarinen ◽  
O. Widholm
Keyword(s):  
Binding Proteins ◽  
Maturation Process ◽  
Hormone Binding ◽  
Maximal Level ◽  
Continuous Increase ◽  
Mean Values ◽  
Thyroxine Binding Globulin ◽  
Before And After ◽  
Free Thyroxine Index ◽  
Level 1

ABSTRACT In an endocrine survey of healthy girls aged 8 to 20 years before and after the menarche, the serum thyroxine (T4), uptake of triiodothyronine by Sephadex (T3U), and the binding capacities of thyroxine binding globulin (TBG) and pre-albumin (TBPA) were measured, and a free thyroxine index (FTI = T4 × T3U) was calculated. The subjects were grouped according to skeletal age (SA) until the menarche and after this in the post-menarcheal age (PMA), expressed in years. T4 and FTI increased concomitantly and reached peak values of 8.40 μg/100 ml and 8.40, respectively, at 2–3 years PMA. The corresponding mean values for post-menarcheal girls (7.74 μg/100 ml and 7.51) differed statistically significantly from the means before the menarche (7.03 μg/ 100 ml and 6.75). The TBG remained virtually unchanged during the whole period, whereas the TBPA showed a continuous increase and reached a maximal level 1–2 years after the menarche. The maturation process in girls in some way involves an increase in the total and free T4 level which is not dependent on hormone binding proteins.

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.

Familial elevation of serum thyroxine binding globulin in an Icelandic family

1984 ◽  
Vol 107 (3) ◽  
pp. 352-356 ◽  
Author(s):  
G. A. Sigurdsson ◽  
G. Arnason ◽  
Th. V. Gudmundsson ◽  
M. Kjeld ◽  
L. Franzson ◽  
...  
Keyword(s):  
X Chromosome ◽  
Family Members ◽  
Elevated Serum ◽  
Pedigree Data ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Mode Of Inheritance

Abstract. A kindred of four generations with inherited elevation of serum thyroxine binding globulin (TBG) is reported. To our knowledge this is the twelfth kindred reported with this disorder. Of the 35 family members studied, 10 females and 5 males had elevated serum TBG. The patients were clinically euthyroid. The pedigree data was consistent with an X-chromosome linked mode of inheritance.

Gender-related differences of serum thyroxine-binding proteins in the rat

1990 ◽  
Vol 123 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Charles H. Emerson ◽  
Joseph H. Cohen ◽  
Ruth A. Young ◽  
Sharon Alex ◽  
Shih-Lieh Fang
Keyword(s):  
Binding Proteins ◽  
Binding Capacity ◽  
Gonadal Hormones ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Testosterone Administration ◽  
The Relationship

Abstract. Because little information is available, studies were performed to determine the relationship between gender and sex steroid status on serum T4 binding proteins in the rat. The binding capacity of serum thyroxinebinding globulin was greater in female rats than in male rats (27 ± 1.3 vs 18.0 ± 1.3 nmol/l, p<0.01) and in fasted female rats than in fasted male rats (64.4 ± 2.6 vs 30.8 ± 2.7 nmol/l, p<0.01). The binding capacity of serum transthyretin was lower in female rats than in male rats (2.1 ± 0.1 vs 3.1 ± 0.1 μmol/l, p < 0.01). Neither ovariectomy or orchidectomy affected the binding capacity of serum thyroxine-binding globulin and it was not increased in ovariectomized rats treated with estrogen. Orchidectomy did not cause a decrease in the binding capacity of serum transthyretin and testosterone administration did not increase it. In contrast, ovariectomy caused an increase in the binding capacity of serum transthyretin (Intact = 2.2 ± 0.1 vs ovariectomized = 2.8 ± 0.1 μmol/l, p <0.01) and estrogen administration caused a decrease (ovariectomized = 2.8 ± 0.1 vs ovariectomized + E2 = 1.9 ± 0.1 μmol/l, p <0.05). The results indicate that the binding capacity of serum thyroxine-binding globulin is higher in female rats than in male rats but this difference is not due to differences in the secretion of gonadal hormones. The binding capacity of transthyretin is lower in female rats than in male rats. This is probably due to the higher circulating levels of estrogen in the female compared to the male.

NORMAL RESPONSE TO THYROTROPHIN RELEASING HORMONE (TRH) IN FAMILIAL THYROXINE-BINDING GLOBULIN DEFICIENCY

1975 ◽  
Vol 80 (2) ◽  
pp. 297-301 ◽  
Author(s):  
E. Hansen ◽  
C. Kirkegaard ◽  
Th. Friis ◽  
K. Siersbæk-Nielsen
Keyword(s):  
Total Serum ◽  
Trh Test ◽  
Normal Response ◽  
Thyrotrophin Releasing Hormone ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Releasing Hormone ◽  
Euthyroid State ◽  
Serum Tsh

ABSTRACT The response in serum thyrotrophin (TSH) to thyrotrophin releasing hormone (TRH) has been studied in 5 euthyroid patients with familial thyroxine-binding globulin (TBG) deficiency. Total serum thyroxine (T4), serum triiodothyronine (T3) and free T4 index and free T3 index were significantly and equally decreased, but in spite of these findings the serum TSH and the response to TRH was normal. The TRH test seems to be a better indicator of the euthyroid state in familial TBG deficiency than the measurement of free T4 and free T3 in serum.

Evaluation of serum triiodothyronine and adjusted triiodothyronine (free triiodothyronine index) in pregnancy.

1977 ◽  
Vol 23 (3) ◽  
pp. 490-492 ◽  
Author(s):  
M E Parslow ◽  
T H Oddie ◽  
D A Fisher
Keyword(s):  
Free Thyroxine ◽  
Free Triiodothyronine ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Free Thyroxine Index ◽  
Total Triiodothyronine ◽  
Total Thyroxine ◽  
Highly Correlated ◽  
Normal Men ◽  
Male Subjects

Abstract We measured serum thyroxine (free and total), triiodothyronine (free and total), thyroxine-binding globulin, and triiodothyronine uptake by talc in 97 normal men and 50 pregnant women. Mean serum thyroxine and triiodothyronine concentrations were higher in the pregnant subjects (104 vs. 78 mug/liter and 1.69 vs. 1.30 mug/liter) because of a higher mean thyroxine-binding globulin concentration (70 vs. 38 mg/liter). Mean triiodothyronine uptake by talc was lower in the pregnant subjects (0.82 vs. 1.03). Mean free thyroxine concentrations were similar in the two groups, but mean free triiodothyronine concentrations were 10% lower in the pregnant subjects. Triiodothyronine uptake by talc and the diayzable thyroxine and triiodothyronine fractions were highly correlated (r = 0.85 and r = 0.82, P less than 0.001). Calculated free thyroxine index and free triiodothyronine index values (hyroxine and triiodothyronine indirectly adjusted, using triiodothyronine talc uptake to compensate for differences in thyroxine-binding globulin concentration), were statistically similar (84 vs. 82 and 1.38 vs. 1.34) in pregnant and male subjects. The results indicate that the total triiodothyronine concentration can be normalized on the basis of the triiodothyronine uptake by talc to correct for variations in thyroxine-binding globulin concentration.

Serum free thyroxine in patients with T3-toxicosis

1985 ◽  
Vol 110 (3) ◽  
pp. 354-359 ◽  
Author(s):  
Enio Martino ◽  
Alessandro Pacchiarotti ◽  
Fabrizio Aghini-Lombardi ◽  
Lucia Grasso ◽  
Giovanni Bambini ◽  
...  
Keyword(s):  
Clinical Evidence ◽  
Elevated Serum ◽  
Normal Serum ◽  
Free Thyroxine ◽  
Total Serum ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Serum Thyroxine ◽  
Free Thyroxine Index ◽  
Serum Free Thyroxine

Abstract. The serum free thyroxine concentration was measured by direct radioimmunoassay in 38 untreated T3-thyrotoxic patients with elevated serum total and free triiodothyronine, normal serum thyroxine and free thyroxine index, no TSH response to TRH, and with clinical evidence of hyperthyroidism. An elevation of circulating free thyroxine values was observed in 58% of the patients, whereas total serum thyroxine concentration was within the normal range. It is suggested, therefore, that T3-thyrotoxicosis should be reserved for patients with elevated serum total T3 and free T3 concentrations and normal serum total T4 and free T4 concentrations. Serum thyroxine-binding globulin concentrations were significantly lower (P < 0.025) in patients with an elevated serum free thyroxine (18.7 ± 3.6 μg/ml: mean ± sd) as compared with those in patients with a normal free thyroxine concentration (23.4 ± 2.6 μg/ml). In addition, no daily fluctuations in total and free thyroxine concentration were observed in 6 patients over a 4–8 day period.

scholarly journals Ratio of Thyroxine to Thyroxine-Binding Globulin

1981 ◽  
Vol 18 (2) ◽  
pp. 93-96 ◽  
Author(s):  
C F Cusick
Keyword(s):  
Reference Range ◽  
False Positives ◽  
Patient Data ◽  
Reference Ranges ◽  
Thyroid Status ◽  
False Negatives ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Protein Levels ◽  
Serum T4

The thyroxine:thyroxine-binding globulin ratio in serum (T4:TBG) has been proposed as a measure of thyroid status unaffected by altered binding protein levels. Here 320 apparently euthyroid patients are used to derive euthyroid ranges for serum thyroxine concentrations at specific TBG levels. These ranges are compared with those predicted by a T4:TBG reference range derived from the same patient data. The comparison suggests that the ratio would give false positives for hyperthyroidism at low TBG levels and false negatives at high TBG levels. To overcome this the use of graphical reporting of results or the relation of patient results to empirical reference ranges appropriate to the TBG level is suggested.

Sign in / Sign up

Export Citation Format

Share Document