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The lack of nocturnal serum thyrotropin surge in patients with nontoxic nodular goiter may predict the subsequent occurrence of hyperthyroidism.

TSH secretion, with particular regard to the nocturnal TSH surge, was evaluated in 115 subjects with non-toxic nodular goiter. All patients were clinically and biochemically euthyroid. After 18-36 months of follow-up (mean, 24 months), hyperthyroidism occurred in 21 (18%; group 1), while the remaining 94 remained euthyroid (82%; group II). The analysis of hormonal data at the time of first observation showed that the 2 groups had similar total and free T4 and T3 serum concentrations. Morning serum TSH values in group I were lower than those in group II patients (0.6 +/- 0.1 vs. 1.1 +/- 0.1 mU/L; P less than 0.001); this difference was even more striking for the nocturnal values (0.6 +/- 0.1 vs. 2.2 +/- 0.2 mU/L; P less than 0.0001); nocturnal values were significantly lower than morning values in group II, but not in group I. The mean peak TSH value after TRH was also significantly reduced in group I (5.5 +/- 0.4 vs. 9.2 +/- 0.7 mU/L; P less than 0.001). Morning TSH values in group II did not differ from those in controls (1.3 +/- 0.1 mU/L), whereas nocturnal and TRH stimulated peak TSH values were slightly but significantly lower. The nocturnal serum TSH values in control subjects were 62-390% higher than morning values. The nocturnal TSH surge was abolished in 18 of 21 (86%) group I patients and in 7 of 94 (8%) group II patients. TRH testing resulted in an absent or blunted TSH responses in 5 subjects in group I and 6 in group II. Analysis by the Galen and Gambino predictive model; comparing the abolition of the nocturnal TSH surge and the abnormal TRH test as predictors of the subsequent occurrence of hyperthyroidism, showed that the former had higher sensitivity (86% vs. 24%) and predictivity (72% vs. 45%). In conclusion, the results of the present study demonstrate that the evaluation of the nocturnal TSH surge may be useful in identifying patients with nontoxic nodular goiter in whom hyperthyroidism may eventually occur. Patients who lack the nocturnal serum TSH surge are more prone to develop thyroid hyperfunction; their thyroid status should, therefore, be more carefully and frequently monitored.

Adult↗

The role of chorionic gonadotropin in transient hyperthyroidism of hyperemesis gravidarum.

Biochemical evidence of hyperthyroidism is frequently encountered in hyperemesis gravidarum, but its relationship to the cause of hyperemesis is unknown. We studied the relationship of serum hCG, thyroid function, and severity of vomiting among 57 hyperemesis patients and 57 controls matched for gestational age. TSH was suppressed in 60% of hyperemesis patients and 9% of controls. hCG correlated directly with free T4(r = 0.45, P < 0.001) and inversely with TSH (r = -0.48, P < 0.001). Hyperemesis patients had significantly greater mean serum hCG, free T4, total T3, and estradiol, and lesser serum TSH compared to controls. Hyperemesis patients with suppressed TSH had significantly greater free T4 and hCG compared to those with TSH in the normal range. Control and hyperemesis subjects were divided into four groups based on the severity of vomiting. The degree of biochemical hyperthyroidism and hCG concentration varied directly with the severity of vomiting. Unextracted serum was tested for thyrotropic activity by measuring its effect on iodide uptake in cultured FRTL-5 rat thyroid cells. Thyrotropic activity correlated with serum hCG (r = 0.50, P < 0.001). These data show that biochemical hyperthyroidism is a common finding in patients with hyperemesis gravidarum and suggest that hCG is the thyroid stimulator in this state. The increased estradiol concentration in patients with hyperemesis gravidarum may be attributed to the effects of hCG on steroidogenesis.

Acute Disease↗

Use of sodium ipodate in management of hyperthyroidism in subacute thyroiditis.

Five hyperthyroid patients (two men and three women) with typical features of subacute thyroiditis were treated with sodium ipodate (Oragrafin; 0.5 g, orally daily or every other day) for 15-60 days; the treatment was stopped when both serum T4 and T3 levels were normal. All patients studied demonstrated a prompt normalization of serum T3, improvement in clinical symptoms of hyperthyroidism, and/or weight gain. We observed no side-effects of treatment with sodium ipodate. Our data suggest that sodium ipodate is a safe and effective agent for management of hyperthyroidism in subacute thyroiditis.

Adult↗

Treatment of hyperthyroidism with a combination of methimazole and cholestyramine.

The entero-hepatic circulation of thyroid hormones is increased in thyrotoxic states. Based on this observation, the use of ionic exchange resins to bind thyroid hormones in the intestine has been tried. The present study evaluates the effectiveness of cholestyramine as an adjunctive therapy in the management of hyperthyroid Graves' disease. Thirty patients with newly diagnosed hyperthyroid Graves' disease were randomly assigned to one of the following treatment groups: methimazole, propranolol and cholestyramine for 4 weeks (group I); methimazole and propranolol for 4 weeks (group II); methimazole, propranolol, and cholestyramine for 2 weeks, followed by 2 weeks of methimazole and propranolol (group III). At the end of the study, total and free T4 as well as T3 levels had decreased more in group I compared with group II: 61%, 78%, 68% in group I compared with 43%, 65%, 50% in group II (P = 0.037 for T4, P = 0.038 for free T4, P = 0.012 for T3). Group III behaved like group I while patients were receiving cholestyramine, but once the drug was discontinued, the rate of decline of thyroid hormones slowed down. We conclude that cholestyramine represents an effective and well-tolerated adjunctive therapy in patients with hyperthyroid Graves' disease, and it produces a more rapid and complete decline in thyroid hormone levels in these patients.

Cholestyramine Resin↗

Catecholamine-induced adipocyte lipolysis in human hyperthyroidism.

Increased lipid mobilization in thyrotoxicosis is attributed to amplification of catecholamine action in fat cells by thyroid hormones. We investigated the adrenergic regulation of lipolysis in isolated sc abdominal fat cells obtained from 14 patients with thyrotoxicosis and 18 control subjects. Ten of the hyperthyroid subjects were also reinvestigated after antithyroid treatment. The thyrotoxic state was associated with a 3-fold increase in maximum norepinephrine-induced lipolysis (P < 0.005), unaltered sensitivity to dobutamine (selective beta 1-adrenoceptor agonist) and clonidine (selective alpha 2-adrenoceptor agonist), but 15 times enhanced sensitivity to terbutaline (selective beta 2-adrenoceptor agonist; P < 0.01). Moreover, thyrotoxicosis was accompanied by a 3-fold increase in beta 2-adrenoceptor number (P < 0.005), but unchanged beta 1-adrenoceptor levels. Further, the lipolytic effects of dibutyryl cAMP (activating protein kinase A and thereby hormone-sensitive lipase) and forskolin (activating adenylate cyclase) were about 60% enhanced (P < 0.005). No change in the maximum activity of the hormone-sensitive lipase could be demonstrated in the hyperthyroid state compared to that in the euthyroid state. The observed abnormalities in lipolysis and beta 2-adrenoceptor number were normalized after antithyroid treatment. It is concluded that in human hyperthyroidism, the interactions between thyroid hormone and catecholamines in adipocytes involve abnormalities at both receptor and postreceptor levels. The former mechanism seems to be a selective increase in the expression of the beta 2-adrenoceptors. The latter mechanism involves increased ability of cAMP to activate hormone-sensitive lipase, but not a change in maximum enzyme capacity.

Adipocytes↗

Antiresorptive therapy in hyperthyroid patients: longitudinal changes in bone and mineral metabolism.

The effect of antiresorptive therapy with nasal calcitonin (CT) in recently diagnosed hyperthyroid patients on conventional medical therapy as well as the evolution of bone metabolism were assessed. Forty-five patients with recent-onset hyperthyroidism (<12 weeks) were sex and menopause stratified and randomly allocated to treatment with carbimazole (Neotomizol), carbimazole plus low dose CT (Calsynar; 100 IU/day, 2 days/week), or carbimazole plus high dose CT (Calsynar; 100 IU/day, 14 days/month). Bone mineral density was measured by dual x-ray absorptiometry in lumbar spine, femoral neck, and Ward's triangle at 0, 9, and 18 months of treatment. We also determined free T4, free T3, TSH, osteocalcin, total and bone alkaline phosphatases, tartrate-resistant acid phosphatase, type I collagen C telopeptide, and urinary hydroxyproline every 3 months of follow-up. No significant difference was observed among treatments. A euthyroid state was attained at 3 months. Bone mass increased significantly at the 9 month evaluation (P < 0.05), with a 5-10% net gain during follow-up. Nevertheless, final bone mass was 4-8% smaller than expected. Bone formation markers were increased at 0 and 3 months, with reductions at 6-9 months; resorption bone markers showed a significant reduction at the 3 month evaluation. These results indicate that the euthyroid state partially reduces hyperthyroidism-associated osteopenia, with a bone mass recovery period during the 6-9 early months of effective treatment. This recovery phase is characterized by raised bone formation markers and reduced bone resorption markers. The treatment with nasal CT at the doses assayed has no additional effect over that of attainment of the euthyroid state.

Absorptiometry, Photon↗

Changes in parameters of bone and mineral metabolism during therapy for hyperthyroidism.

Hyperthyroid patients have high bone turnover and negative calcium and phosphorus balance often associated with mild osteopenia. Early during antithyroid treatment bone turnover decreases, the mineral balance is converted to positive, and sometimes hypocalcemia occurs. The aim of this investigation was to study the mechanisms of the changes in some parameters of bone and mineral metabolism after treatment of thyrotoxicosis. Thirteen newly diagnosed patients with Graves' disease (seven postmenopausal women, four premenopausal women, and two men) were studied longitudinally, every 6 weeks, for 1 yr after commencing antithyroid treatment with methimazole. Mean serum calcium and phosphorus were both slightly above the normal mean at week 0 and decreased significantly (by 10% and 24%, respectively) during treatment. Fasting urinary calcium was 236 +/- 4 (mean +/- SEM) mg/g creatinine, and the fractional excretion of Ca was 2.0 +/- 0.33% before treatment; both fell significantly to minimums of 61 +/- 20 mg/g and 0.6 +/- 0.16%, respectively. Urinary phosphorus was 282 +/- 60 mg/g creatinine, and the fractional excretion of phosphorus was 3.3 +/- 0.6% before treatment; both increased significantly to 452 +/- 40 mg/g and 8.4 +/- 1.0%, respectively, during treatment. The z-scores were calculated from the mean and SD ofthe respective control groups. The z-score of urinary N-telopeptides of type I collagen (U.NTx) was 9.3 +/- 1.3 at week 0 and declined exponentially, but failed to normalize after 1 yr of antithyroid treatment. The serum alkaline phosphatase (ALP) z-score was initially 2.2 +/- 0.2, increased to 6.0 +/- 1.0 at week 6, and declined slowly there after to 1.0 +/- 1.1 at week 54. The serum osteocalcin (OC) z-score showed a temporal pattern similar to that of ALP. It was initially 2.2 +/- 0.2, increased to 4.0 +/- 0.6 at week 6, and later declined slowly to 0.7 +/- 0.5 at week 54. The failure of the markers of bone turnover to normalize after 1 yr of therapy indicates an on-going high rate of bone turnover despite the attained euthyroidism. The uncoupling index (UI = z-score of U.NTx minus z-score of OC) was 7.1 +/- 1.2 before treatment, indicating unbalanced bone turnover in favor of bone resorption, and fell close to zero at week 30 of treatment. Pretreatment plasma PTH was suppressed slightly to 2.17 +/- 0.47 pmol/L and rose significantly during treatment, reaching a plateau of 5.27 +/- 0.78 at week 12. In all postmenopausal women PTH increased above the upper limit of normal (6.84 pmol/L). Pretreatment serum 25-hydroxyvitamin D was normal and remained unchanged during treatment, whereas 1,25-dihydroxyvitamin D was initially subnormal and rose to normal level after treatment. There was a significant positive linear correlation between PTH and U.NTx after week 12. PTH was also significantly correlated with ALP, but not with OC. ALP and OC were significantly correlated. A significant positive correlation was found between T3 and U.NTx, and a negative correlation was found between T3 and each of the formation markers (ALP and OC) over the 0- to 12-week interval. The latter correlations and the very high pretreatment UI indicate some inhibitory effect of the high thyroid hormone levels on the osteoblasts. The marked and sustained elevation of PTH, more pronounced in the postmenopausal women, during the first year of treatment of hyperthyroidism seems to play a pivotal role in maintaining a relatively high rate of bone turnover despite euthyroidism, and in the conservation of calcium by reducing renal calcium excretion and increasing calcium absorption (via 1,25-dihydroxyvitamin D). It may also account in part for the additional rise of the bone formation markers by an anabolic effect on the osteoblasts. Endogenous PTH may be important in the restoration of bone mineral density of treated hyperthyroid patients.

Adult↗

Use of oral cholecystographic agents in the treatment of amiodarone-induced hyperthyroidism.

We describe here five cardiac patients with type II amiodarone-induced hyperthyroidism who were treated prospectively with a combination of an oral cholecystographic agent (sodium ipodate, Oragrafin, or sodium iopanoate, Telepaque) and a thionamide (propylthiouracil or methimazole); amiodarone was discontinued in all patients. All patients improved substantially clinically within a few days of treatment and became euthyroid or hypothyroid in 15-31 wk when treatment was discontinued. Four of the five became hypothyroid and required long-term treatment with L-T(4); the remaining patient was euthyroid, but died from cardiomyopathy and congestive heart failure at 29 wk, when he had been off oral cholecystographic agent and thionamide for 6 wk. We did not find any clinical or biochemical adverse effects of the treatment. Our study suggests that a combination of oral cholecystographic agent and thionamide is a safe and effective treatment of type II amiodarone-induced hyperthyroidism. Data also suggest that hypothyroidism is a common end result of type II amiodarone-induced hyperthyroidism.

Administration, Oral↗

Soluble Fas is increased in hyperthyroidism independent of the underlying thyroid disease.

In Hashimoto's thyroiditis, Fas-induced apoptosis is one of the mechanisms leading to cell destruction, whereas thyroid tissue in Graves' disease is prevented from it. The soluble form of the Fas molecule produced by alternative splicing prevents from apoptosis. We measured soluble Fas in the sera of 112 patients with Graves' disease, 21 patients with toxic goiter, and 24 patients with subclinical hyperthyroidism due to suppressive therapy with levothyroxine after near-total resection of the thyroid gland for nodular goiter. Soluble Fas was increased in thyrotoxic patients, toxic goiter, and patients with subclinical hyperthyroidism. Decreased levels of soluble Fas were found in euthyroid patients with Graves' disease after surgery, whereas soluble Fas was normal in euthyroid patients with Graves' disease receiving antithyroid drug treatment and in patients in stable remission. There was a good correlation between soluble Fas with free T(3) (r = 0.6) and free T(4) (r = 0.5). Our results show that soluble Fas is increased in hyperthyroidism independent of the underlying thyroid disease.

Adult↗

A prospective controlled study of the impact of hyperthyroidism on reproductive function in males.

The aim of this prospective controlled study was to ascertain the effect of hyperthyroidism on sperm quality and composition. We studied 23 thyrotoxic male patients, aged 43.8 +/- 2.4 yr (mean +/- SEM), and 15 healthy male controls of approximately the same age (42.2 +/- 2.2 yr). Two semen analyses at intervals of 2-3 wk were obtained before and about 5 months after euthyroidism was achieved either by methimazole alone (14 patients) or (131)I plus methimazole (9 patients). Total fructose, zinc (Zn), and magnesium (Mg) were also measured in seminal plasma in 16 patients, because 7 had semen volume less than 2 ml. In the control group semen analysis was performed only once. Mean (+/-SEM) semen volume was within normal range both in patients (3.3 +/- 0.2 ml) and controls (3.5 +/- 0.4 ml; P = NS). Mean sperm density was lower in patients, although the difference compared with controls did not reach statistical significance (35.7 +/- 5.3 vs. 51.5 +/- 6.1 x 10(6)/ml; P = 0.062). The same was found with sperm morphology (68 +/- 7% vs. 78 +/- 8%; P = NS). Finally, mean motility was lower in thyrotoxic males than in controls (28 +/- 8% vs. 57 +/- 7%; P < 0.01). After treatment, sperm density and motility improved [35.7 +/- 5.3 vs. 43.3 +/- 6.5 x 10(6)/ml (P = NS) and 28 +/- 8% vs. 45 +/- 7% (P < 0.05), respectively], but sperm morphology did not change (68 +/- 7% vs. 70 +/- 6%; P = NS). Mean values for fructose, Zn, and Mg did not differ between controls and patients either before or after achievement of euthyroidism [9.2 +/- 0.7, 3.0 +/- 0.5, and 4.2 +/- 0.7 nmol/liter vs. 8.6 +/- 0.9, 3.0 +/- 0.5, and 4.7 +/- 0.8 nmol/liter (patients before) and 9.1 +/- 0.7, 3.1 +/- 0.6, and 4.5 +/- 0.9 nmol/liter (patients after treatment) for fructose, Zn, and Mg, respectively]. Moreover, according to the treatment given, no statistically significant differences were found before or after treatment. Finally, seminal plasma fructose, Zn, and Mg levels did not correlate with sperm parameters or with pretreatment thyroid hormone levels. In conclusion, the results of our study indicate that male patients with hyperthyroidism have abnormalities in seminal parameters, mainly sperm motility. These abnormalities improve or normalize when the patients become euthyroid. Restoration of sperm parameters was independent of the treatment provided for the hyperthyroid syndrome. Moreover, seminal plasma elements, such as fructose, Zn, and Mg, did not correlate with sperm density, motility, or morphology.

Adult↗

An approach to mediastinal masses associated with hyperthyroidism.

Benign thymic hyperplasia (BTH) is a known feature of hyperthyroidism, but is infrequently appreciated by clinicians. In most cases thymic enlargement is minimal; however, it may occasionally present as an appreciable anterior mediastinal mass. While surgical resection is a common approach to such a mass, recognition of the benign nature of BTH and its regression following treatment of hyperthyroidism would prevent a major surgical procedure. We present three cases of BTH associated with hyperthyroidism and describe our approach to this syndrome.

Adolescent↗

The problem of exogenous subclinical hyperthyroidism.

Over the past two decades a plethora of publications and clinical practice data have established that subclinical thyroid dysfunction is a common condition occurring much more frequently than the overt expression of thyroid disease. Subclinical hypothyroidism is considered to be the most common of these entities. However, far more common and relatively less studied is exogenous sublinical hyperthyroidism (SubHyper) caused by L-thyroxine (T4) administration to thyroidectomized or hypothyroid patients or patients with simple or nodular goiter. Despite iodination, simple goiter is still prevalent and single or multiple nodules are now detected by ultrasound screening in 25-30% of adults, who are accordingly frequently given long-term T4 treatment. Approximately half of European Endocrinologists administer T4 permanently to patients with the above entities with the aim of suppressing TSH levels. Furthermore, in the USA the Colorado Study demonstrated that 40% of patients receiving thyroid hormones had abnormal [corrected] TSH levels (i.e. lower than 0.3 or higher than 5.1 mU/L); of these, 0.9% had hyperthyroidism and 20.7% subclinical hyperthyroidism [corrected] These facts render exogenous SubHyper an everyday problem for the endocrinologist. Exogenous SubHyper differs in many aspects from endogenous, its principal difference being that it is an iatrogenic thyroid disorder induced by the endocrinologist. The management of exogenous SubHyper relies on appropriate adjustment of T4 dosage taking into consideration a) individual requirements in T4, sex, age and the presence of cardiovascular disease or other co-morbidity, b) the recognition that small changes in serum FT4 have a logarithmic effect on TSH, c) the variability of FT4-TSH interactions between individuals, d) the instability of T4 preparations and its bioavailability, and e) the values of serum FT4 and FT3 that accompany a suppressed TSH. This last parameter is of importance since it is the free thyroid hormones values in the serum that generate and reflect the thyroid metabolic state of the organism rather than the degree of TSH suppression.

Dose-Response Relationship, Drug↗

[Increased liver nuclear triiodothyronine-receptors associated with mitochondrial alpha-glycerophosphate dehydrogenase activity in hyperthyroid rats (author's transl)].

The effects of triiodothyronine (T3) on binding characteristics of nuclear T3-receptors were examined in rats. The T3-receptors were extracted by 0.4M KCl from the liver nuclei isolated from the following 3 groups of rats: (1) thyroidectomized, (2) thyroidectomized and treated with 230 ng T3/100 g body weight/day for 3 days, and (3) thyroidectomized and treated with 40 micrograms T3/100 g body weight/day for 3 days. Their association constant (Ka) and maximal binding capacity (Cmax) for T3 were determined by Scatchard analyses with and without correction for endogenous T3. The amount of endogenous T3 bound to the nuclear extracts was estimated on the basis of a specific activity of [125I]-T3 injected 2 hours before sacrifice. It was demonstrated that Cmax values corrected for the endogenous T3 were 2.5 times greater in severely hyperthyroid than in hypothyroid rats. By contrast, corrected values for Ka remained unchanged in all 3 groups of rats, although uncorrected values were apparently decreased in the severely hyperthyroid rats. Validity of the correction was supported by the in vitro experiments preincubated with stable T3. The yields of nuclear protein-125I-T3 complex in the procedure of extraction and the contents of DNA per g of liver were nearly the same in the 3 groups. The increase in Cmax of the nuclear receptors was directly related to mitochondrial alpha-glycerophosphate dehydrogenase activity. The results obtained indicate that the Cmax of nuclear T3-receptors is increased in a severely hyperthyroid state, related to hormonal action, and that the correction for endogenous T3 is essential for an accurate estimation of Ka and Cmax.

Animals↗

[Case of hyperthyroidism with pancytopenia].

A case of hyperthyroidism associated with pancytopenia has been reported. A 51-year-old woman was hospitalized for the investigation of struma, peripheral edema and fatigue. Hormonal studies revealed hyperfunction of the thyroid gland. Hematological examinations showed normocytic normochromic anemia, leukopenia and thrombocytopenia with hyperplastic bone marrow and increased serum iron levels. Elevations of the anti-thyroidal antibody and anti-microsomal antibody, and a decrease in CH50 titer were observed. A Coombs' test and anti-leukocytic antibody and anti-thrombocytic antibody tests were negative. The numbers of erythrocyte and thrombocyte were normalized after the administration of methimazole for three months as were the findings of the bone marrow and the serum iron level. However, leukopenia was maintained due to the effect of methimazole. It should be suggested that the etiology of pancytopenia might be due to hyperthyroidism. Although the mechanism of pancytopenia in a patient with hyperthyroidism is unclear, it might be related to the reduced life-span of whole blood components and/or partially to the autoimmune mechanism.

Female↗

[A case of chemical hyperthyroidism induced by antiarrhythmic agent amiodarone].

Amiodarone, an antiarrhythmic agent, is known to occasionally induce alterations in thyroid function because of its iodine content and ability to inhibit T4 5'-monodeiodination. We herein describe the drug-induced chemical hyperthyroidism in a diabetic patient with ventricular premature beats. A 46-year-old man with well controlled diabetes mellitus revealed neck swelling during a 4 months' treatment with amiodarone for his frequent occurrence of ventricular premature beats. Physical findings were unremarkable other than grade III diffuse struma. Routine laboratory studies were almost normal. The results of thyroid function studies showed hyperthyroidism, including increases in T4 and free T4, slight increases in T3 and free T3, a marked increase in reverse T3 and a decrease in 123I 24-h uptake. TSH was low and did not respond to TRH. Antithyroid antibodies and TSH receptor antibodies were negative. The findings of the thyroid biopsy were unremarkable except for a mild follicular hyperplasia. After cessation of the drug, T3 and free T3 were returned to normal within 2 weeks, T4 and free T4 within 2 months and reverse T3 after 6 months. These data suggest that the struma and chemical hyperthyroidism observed in our patient were induced by amiodarone treatment.

Amiodarone↗

[TSH receptor antibody in hyperthyroid patients due to Graves' disease treated with antithyroid drugs].

As an immunologic process, TSH receptor antibody (TRab) may be synthesized by the lymphocytes within the thyroid gland. Two techniques were devised to express this TRap activity: a) thyroid stimulating immunoglobulin (TSI) expressed as thyroid c AMP synthesis and b) TSH binding inhibiting immunoglobulin (TBII) expressed as TSH displacement. In general, serum TSI and TBII activity correlated well with each other in hyperthyroid patients. Measurement of TSI and TBII is useful to assess improvement of immunologic abnormality induced by antithyroid drugs. The data so far gathered indicated that TRab disappears from the blood in about 70-80% of hyperthyroid patients in response to antithyroid drugs. However, this does not indicate that intrathyroidal TRab synthesis has ceased, since thyroglobulin is still secreted supernormally and T3 fails to suppress the thyroid in some patients. On the other hand, normalization of thyroglobulin and absence of TRab in the blood indicated complete normalization in the patients as evidenced by positive T3 suppressibility. By using a number of new drugs, further efforts must be made to completely normalize immunologic abnormality in 100% of patients. Recurrence of hyperthyroidism of Graves' disease is generally associated with re-appearance of TRab in the blood in most of the recurrent patients after discontinuation of antithyroid drugs.

Adult↗

A case of TSH receptor antibody-positive hyperthyroidism with functioning metastases of thyroid carcinoma.

The presence of TSH receptor antibody (TRAb) is rarely responsible for hyperthyroidism due to metastatic lesions of thyroid carcinoma. A 70-year-old woman was incidentally found to be thyrotoxic around the time that external irradiation was performed for multiple bone metastases 9 years after subtotal thyroidectomy for follicular carcinoma. Hyperthyroidism persisted after oral administration of thiamazole. Relevant laboratory data were as follows: FT4 9.6 ng/L, FT3 7.3 ng/L, TSH <0.19 mU/L, TBII 70, TSAb 735, and Tg 32,000 microg/L. 131I-total body scan showed 131I accumulation in the occipital bone, cervical vertebra, thoracic vertebra, ilium, and residual thyroid gland. Since the ilium uptake (11.6) was markedly higher compared to the residual thyroid gland uptake (0.14), four subsequent 131I therapies were performed. The patient became hypothyroid, and TBII became negative. TSAb became negative after the first 131I-therapy but has increased again to 204 at present. Tg was 1,962 microg/L despite high TSH levels. 131I accumulation in the residual thyroid, cervical vertebra, and thoracic vertebra disappeared. Also 131I accumulation in the ilium has gradually decreased, but the image in the occipital bone has become markedly distinctive. This is a rare case characterized by TRAb-positive hyperthyroidism, by T3-predominant thyrotoxicosis, and by stronger accumulation of 131I in the metastatic tumor than in the residual thyroid gland. Thus, the response to TRAb and 131I-therapy is different among metastatic thyroid tissues.

Adenocarcinoma, Follicular↗

Changes in plasma glucose, insulin (IRI), glucagon (IRG) and free fatty acids (FFA) following alanine loading in hyperthyroid patients.

The responses of plasma glucose, insulin (IRI), glucagon (IRG) and free fatty acids (FFA) following alanine loading (0.1 g/kg) were observed in 9 control subjects and 7 hyperthyroid patients, before and after restoration of thyroid function to normal. Despite the persistence of impaired glucose response to alanine, the blunted IRI and IRG responses in the hyperthyroid state were improved with a significant reduction in fasting IRI and IRG after treatment. Markedly increased FFA following alanine loading in hyperthyroid patients was reduced after treatment, but the FFA concentration remained greater than in the control subjects. We tentatively conclude that the impaired alpha and beta-cell responses to alanine were temporarily induced by the direct and/or indirect effects of thyroid hormone excess.

Adult↗