Thyroid Radioiodine Uptake Research Articles

Highly sensitive immunoradiometric assay for TSH and thyroid radioiodine uptake as predictors of thyroid suppression test.

Suppression of TSH and thyroid radioiodine uptake by doses of either T4 or T3 were compared in 33 patients in whom Graves' thyrotoxicosis had been treated with thioamide drugs and the medication was discontinued for at least 4 months. Thyroidal radiodine uptake was suppressed in 19 patients and was not suppressed in the remaining 14 patients. Basal TSH levels before suppression were 2.07 microU/ml in the former, significantly exceeding those of the latter (0.91 microU/ml). A TSH level of at least 1.2 microU/ml before suppression is a good predictor of positive thyroid radioiodine suppression with a predictive value of 76%. A level lower than 0.7 microU/ml before suppression is a good predictor of negative thyroid radioiodine uptake suppression with a predictive value of 89%. The determination of TSH levels before the thyroid suppression test was helpful in predicting the result, but there were limitations. In the thyroid suppression test positive group, circulating T4 was depressed by doses of T3. In them, the magnitude of T4 depression correlated with the levels of thyroid radioiodine uptake before suppression. The levels of TSH correlated neither to changes in T4 nor to those in thyroid radioiodine uptake. This indicates that the thyroid glands which show high radioiodine uptake are sensitive to TSH and are also sensitive to suppression. The elevated sensitivity to TSH probably warrants the disappearance of abnormal thyroid stimulation more precisely.

A method for the radiohalogenation of proteins resulting in decreased thyroid uptake of radioiodine

A procedure is described for the radioiodination of proteins using an iodinated derivative of N-succinimidyl 3(trinbutylstannyl) benzoate (ATE). Adequate removal of unreacted ATE from [ 125I]ATE was necessary for optimal protein radioiodination. Labeling efficiencies of greater than 60% could be obtained after a 20 min incubation of goat IgG with [ 125I]ATE at 4°C. Paired-label experiments with goat IgG labeled with 125I using ATE and 131I using Iodogen demonstrated that use of the ATE reagent for protein labeling significantly reduced ( P < 0.005) the thyroid uptake of radioiodine.

Amiodarone: a common source of iodine-induced thyrotoxicosis.

Amiodarone, a iodine-rich drug widely used in the treatment of tachyarrhythmias, represents one of the most common sources of iodine-induced thyrotoxicosis. The data concerning 58 patients with amiodarone-iodine-induced thyrotoxicosis (AIIT) were analyzed in the present study. Prevalence of AIIT was higher in males than in females (M/F = 1.23/l). Thyrotoxicosis occurred either during treatment with or at various intervals after withdrawal of amiodarone. AIIT developed not only in patients with underlying thyroid disorders, but also in subjects with apparently normal thyroid gland. Classical symptoms of thyrotoxicosis were often lacking, the main clinical feature being a worsening of cardiac disorders. Biochemical diagnosis of AIIT was established by the finding of elevated serum total and free triiodothyronine levels, since elevated serum total and free thyroxine could be found also in euthyroid amiodarone-treated subjects. Twenty-four-hour thyroid radioiodine uptake was very low or undetectable in AIIT patients with apparently normal thyroid glands, while it was inappropriately elevated in patients with underlying thyroid disorders, despite iodine contamination. The role of autoimmune phenomena in the pathogenesis of AIIT appeared to be limited, because circulating thyroid autoantibodies were undetectable in AIIT patients without underlying thyroid disorders or with nodular goiter. Conversely, humoral features of thyroid autoimmunity were mostly found in AIIT patients with diffuse goiter. Treatment of AIIT appeared to be a difficult challenge. Among the 11 patients given no treatment, thyrotoxicosis spontaneously subsided in the 5 patients with apparently normal thyroid gland, whereas the 6 patients with nodular or diffuse goiter were still hyperthyroid 6-9 months after discontinuation of the drug. The administration of high doses (40 mg/day) of methimazole alone proved to be ineffective in most (14/16) patients given this treatment. Twenty-seven patients were treated by methimazole combined with potassium perchlorate (1 g/day). With one exception, euthyroidism was restored within 15-90 days in all cases with underlying thyroid abnormalities, and within 6-55 days in subjects with apparently normal thyroid gland. Thus, the combined treatment appears to be the most effective one, but, due to the potential toxicity of potassium perchlorate, it should be reserved to patients with severe thyrotoxicosis and should be carefully monitored.

Are Pituitary and Thyroid Function Tests Useful for the Monitoring of Antithyroid Drug Treatment and the Post Therapeutic Control of Graves&amp;rsquo; Disease?

The control of Graves' disease patients treated with antithyroid drugs (ATD) involves monitoring the dose of ATD, the duration of therapy and the prediction of the long-term outcome of the disease. The sequential follow-up of free thyroid hormones and ultrasensitive TSH (USTSH) helps in monitoring of ATD therapy, except in patients complemented with thyroid hormones. The normalization of early thyroid uptake of radioiodine or pertechnetate, which seems to be closely related to circulating thyroid-stimulating immunoglobulins, confirms the remission that leads to stopping ATD therapy. The raise of plasma USTSH in a normal range within the six months following ATD withdrawal is another indicator of remission. However, the post therapeutic course of Graves' patients remains unpredictable: late relapses and hypothyroidism may occur despite the normalization of the pituitary-thyroid axis, leading to a yearly clinical control with USTSH evaluation.

A Case of Retropharyngeal Soft-Tissue Swelling: The Definitive Diagnosis Revealed

To the Editor.— In a recent issue, a patient with neck tenderness, fever, and retropharyngeal swelling was described.1The diagnosis of subacute thyroiditis was made on the basis of an increased erythrocyte sedimentation rate, thyroid tenderness, and a markedly depressed thyroid uptake of radioiodine. Treatment with antibiotics and corticosteroids resulted in resolution of the symptoms. The authors made a diagnosis of subacute thyroiditis. Such a conclusion is not supported by the information given. Infectious thyroiditis not uncommonly results in a decreased thyroid radioiodine uptake.2Because the patient received antibiotics (although for only two days), infectious thyroiditis remains a possibility. A negative result on examination of a fine-needle aspirate is not sufficient to rule out infectious thyroiditis. Fine-needle aspiration of the thyroid can provide a definitive diagnosis of subacute thyroiditis,3and only if cytologic or histologic evidence of subacute thyroiditis is obtained can the authors' claim be accepted.

Uninhibited Thyroidal Uptake of Radioiodine Despite Iodine Excess in Amiodarone-Induced Hypothyroidism*

Iodine excess is associated with a low thyroidal radioiodine uptake due to dilution of the radioisotope by the increased stable iodide pool. We studied thyroidal uptake of radioisotopes in cardiac patients with iodine excess due to amiodarone treatment. 99mTc-pertechnetate scintigraphy was performed in 13 patients receiving long term amiodarone therapy. Five patients had a clearly visible thyroid gland, and 8 patients had no or a very faint thyroid image. All patients with positive scans had an increased plasma TSH level, whereas all patients with negative scans had a normal or absent TSH response to TRH. Thyroidal uptake and discharge of 123I were studied in 30 other patients. Group I (n = 11) had normal plasma TSH responses to TRH and no iodine excess, group II (n = 7) had normal TSH responses to TRH and excess iodine from metrizoate angiography in the previous month, group III (n = 7) had normal or decreased TSH responses to TRH while receiving long term amiodarone therapy, and group IV (n = 5) had increased TSH responses to TRH while receiving long term amiodarone therapy. The mean radioiodine uptake value in group I [5.4 +/- 0.8% (+/- SE) at 60 min] was higher than those in group II (2.3 +/- 0.7%; P = 0.009) and group III (0.8 +/- 0.3%; P = 0.0005), but not different from that in group IV (5.3 +/- 1.2%; P = NS). Radioiodine discharge after perchlorate (expressed as a percentage of the 60 min uptake) in group I (10.1 +/- 2.2%) was lower than those in group II (24.9 +/- 10.6%; P = 0.05) and group III (28.8 +/- 5.3%; P less than 0.005), whereas discharge in group IV (58.0 +/- 6.1%) was greater than those in group II (P less than 0.05) and group III (P less than 0.01). In conclusion, 1) thyroid visualization by 99mTc-pertechnetate and thyroid radioiodine uptake during iodine excess are decreased in euthyroid and hyperthyroid patients, but preserved in hypothyroid patients. 2) The organification defect induced by iodine excess is greater in iodide-induced hypothyroidism than in eu- or hyperthyroidism. These findings may be explained by the increased TSH secretion in hypothyroidism and/or by decreased thyroidal concentration of an unknown specific iodinated compound (whose concentration and action vary with the total organic iodine content of the thyroid) that mediates the inhibition of iodide transport.

Prevention and treatment of endemic iodine-deficiency goiter by iodination of a municipal water supply.

A recently described method for the prevention and treatment of endemic iodine deficiency and goiter, introduction of iodine into a public water supply, was tested in Troina, a town of about 13,000 inhabitants in northeast Sicily. There, before initiation of the program, a goiter endemic of moderate severity was present, as evidenced by goiter prevalence of 55% in school children. Iodine deficiency in nongoitrous adults was indicated by daily urinary iodine excretion of 40.7 +/- 2.6 micrograms (mean +/- SE) and 24-h thyroid radioiodine uptake of 50.8 +/- 2.4%. Iodination of the water supply was initiated in November 1979 using a stream-splitting device that diverts a controlled fraction of the total water flow to a canister containing iodine crystals, where the water becomes saturated with iodine (approximately 300 mg/liter) before returning to the main stream. Except for a 15-month interruption during which governmental authorization of the program was being reconfirmed, treatment of the water has continued to the present time, initially at a level of 81 +/- 25 micrograms/liter (mean +/- SD) and since resumption at a level of 46.5 +/- 5 micrograms/liter. Iodination of the water was followed by a prompt and marked reduction in goiter prevalence, and by improvement in biochemical indices of iodine deficiency. By April 1983, overall goiter frequency in school children had declined to 6.1%, and large goiters (WHO Grade 2) had virtually disappeared. By January 1984, daily urinary iodine excretion had increased to 85.6 +/- 6.5 (SEM) micrograms and radioiodine uptake had decreased to 40.7 +/- 4.7%. Serum thyroid-related hormone concentrations were as follows (pretreatment vs. November-December 1983): T4, 5.8 +/- 0.3 vs. 8.4 +/- 0.3 microgram/dl; T3, 1.6 +/- 0.05 vs. 1.2 +/- 0.06 ng/ml; TSH, 3.7 +/- 0.2 vs. 2.2 +/- 0.1 microU/ml; all changes being statistically significant. By late 1983, serum T4, T3, and TSH values in Troina were almost identical to those in Catania, a community in which iodine deficiency is not present (goiter prevalence in school children, 2.2%). In contrast, in Troina serum T4 concentrations were significantly higher and serum TSH concentrations were significantly lower than those in Maniaci, a iodine-deficient town near Troina, in which the water was not iodinated. Iodinated water was well tolerated by the population of Troina, and no adverse effects of water iodination, including any increase in the frequency of hyperthyroidism, was observed. At present prices, the cost of the water iodination program in Troina would be approximately 4 cents (U.S.) per person per year.(ABSTRACT TRUNCATED AT 400 WORDS)

Efficacy of radioiodine urinalysis.

Little exists in the literature to support the efficacy of urinalysis for demonstrating thyroid uptake of radioiodine. A review was made of a variety of kinetic models. Computer analysis and graphics were used to assess the variables in the two models chosen for this study. The applicability of each model was tested by using data obtained from a group of euthyroid subjects. The results indicate that using an integral urine-sampling method and a three-component model yields minimum detectable thyroid uptakes which fall well below required reporting limits. Furthermore, the results show that integral urine samples obtained in the first few hours post exposure may be used to predict major thyroid uptakes in time for effective thyroid blocking.

The nature of thyrotropin stimulation of thyroid function in Japanese quail: Prolonged thyrotropin exposure is necessary to increase thyroidal 125I uptake

1. 1. Single injections of thyrotropin (TSH) increase serum T 4 and thyroidal 32P uptake but not thyroidal 125I uptake regardless of dosage, exposure time or age. Chronic TSH exposure, with 3 or more days of injection, does increase thyroidal 125I uptake. 2. 2. Studies using iodine (I) supplementation indicated that the increased thyroidal radioiodine uptakes seen with chronic TSH administration were not due to an I deficiency in the thyroid resulting from high hormone release. 3. 3. Labeled and unlabeled experiments comparing the effects of single vs. multiple injections of TSH were used to describe the effects of TSH on hormone release, hormone production and thyroidal I uptake.

Long Term Treatment of Graves5 Hyperthyroidism with Sodium Ipodate*

To investigate the long term usefulness of sodium ipodate (Oragrafin) in the management of Graves' hyperthyroidism, we studied the effects of ipodate (500 mg, orally, daily for 23-31 weeks) on serum T3, T4, rT3, and some clinical parameters in five newly diagnosed Graves' hyperthyroid patients. Mean pretreatment serum T3, T4, and rT3 concentrations were 780 ng/dl, 25.4 micrograms/dl, and 118 ng/dl, respectively. One day after the first dose of ipodate, serum T3 decreased by 62% (P less than 0.01), and it was within the normal range thereafter throughout treatment. The serum T4 concentration decreased by 20% (P = 0.09) at 24 h and by 43% (P less than 0.05) at 14 days. Subsequently, serum T4 was 41-65% lower than before treatment throughout the study; rT3 increased 24 h after the first dose of ipodate (118% above baseline; P = 0.1), remained elevated (97-109%) for 10 weeks, and then gradually decreased to the pretreatment level. A marked gain in body weight [5.1 +/- 1.1 (+/- SEM) kg] occurred in all patients. After discontinuation of ipodate, mean thyroid radioiodine (RAI) uptake values increased serially in four patients and were similar to pretreatment values: pretreatment, 74 +/- 6% (+/- SEM); after 7 days, 66 +/- 8%; after 14 days, 71 +/- 7%; after 28 days, 69 +/- 7%. The fifth patients's RAI uptake was 12-16% (vs. a pretreatment value of 48%) from 7-28 days after the end of a 31-week course of ipodate. He remained euthyroid without further treatment for the subsequent 4 months. We conclude that 1) ipodate (500 mg daily) reduces serum T4 and T3 levels as fast and as much as does the 1-g daily dose studied previously; 2) long term use (for 23-31 weeks) of ipodate for the treatment of Graves' hyperthyroidism is clinically feasible; no adverse effects occurred during or after ipodate treatment; and 3) RAI uptake returns to pretreatment levels as early as 7 days after the discontinuation of ipodate. Hence, use of ipodate does not prevent use of 131I therapy for those patients for whom it is otherwise desirable.

Thyroidal uptake of iodine-123 in children using a gamma camera and computer.

The measurement of thyroidal uptake of radioiodine using a gamma camera and computer is described. In 12 children there was good agreement with simultaneous measurements using a probe, while in a further 14 patients the uptake values were consistent with the clinical diagnosis. The technique should be especially useful for infants and small children.

The effects of different maternal dietary iodine concentrations on Japanese quail II. Thyroid function in embryos and hatchlingsi

Embryos (day I4 of the 16.5 day incubation period) and I day old chicks of Japanese quail ( Coturnix japonica) were used to study the effects of egg I on thyroid development. The maternal diets were supplemented with 0–1200 μg I/kg of purified diet. Thyroid function, of embryos and chicks (before feeding), adapted to a wide range of egg I availability. We measured body weights, thyroid weights, thyroidal 125I uptakes, stable I concentrations in thyroid glands and triiodothyronine (T 3) and thyroxine (T 4) concentrations in the serum. With low egg I (maternal diets with <50 μg I/kg) embryonic and chick thyroid glands were hypertrophied, thyroidal I content was very low and thyroidal radioiodine uptakes were high. Serum hormone concentrations were not significantly different from those of embryos and chicks from eggs with higher I contents. Thyroid weights were lowest in young from eggs of hens on the 150 μg I/kg diet, and the other variables studied also indicated this maternal diet provided sufficient egg I for the thyroid function of embryos and hatchlings. With high egg I (maternal diets with 300–1200 μg I/kg) thyroidal radioiodine uptakes were low but thyroidal I incorporation was related to egg I content. Serum hormone concentrations were not significantly altered by high I availability except that serum T 4 concentrations differed in a comparison of the extremes (0 vs 1200 μg I/kg in the maternal diet). As expected, from the consistency of serum hormone concentrations, embryonic growth was not affected by the I content of the eggs. In agreement with earlier studies on quail hens, our results indicate that feed supplementation of 150 μg I/kg is sufficient to meet needs without requiring alterations in thyroid function to maintain serum hormone concentrations. Developing thyroid glands adapt effectively to egg I concentrations of 0.2 to 4.1 μg I/g yolk which result from maternal diets with 0–1200 μg I/kg.

Serum ?-Glutamyl Transferase Activity in Thyrotoxicosis

To the Editor. —We read with interest the article by Azizi 1 in the January Archives and the letter by JimenezAlonso et al 2 and Azizi's reply. 3 We can confirm Azizi's data in a greater number of patients, at least in part. We, too, have studied the serum γ-glutamyl transferase (GGT) levels in untreated Graves' disease (44 patients) and Plummer's disease (ten patients). Our patients were compared with 100 healthy, age- and sex-matched control subjects. The diagnosis of thyrotoxicosis was based on clinical findings and measurement of serum triiodothyronine (T 3 ) and thyroxine (T 4 ) by radioimmunoassay, T 3 resin uptake (T 3 RU), (free T 4 index [FT 4 I] and free T 3 index [FT 3 I] were calculated [T 3 xT 3 RU, T 4 xT 3 RU, respectively]), radioiodine uptake of thyroid at two and 24 hours, and scintiscans (with or without thyrotropin given previously), for patients and controls, respectively. Serum GGT was assayed by a commercial GGT test (Boehringer/Ingelheim, FRG) based on

LONG-TERM TREATMENT OF GRAVES' HYPERTHYROIDISM WITH IPODATE

We have previously reported that ipodate (1g, q.d.) compares favorably to PTU (200 mg, t.i.d.) in the treatment of Graves' hyperthyroid patients in 3-wk therapy (J Clin Endocrinol Metab 54:630, 1982). This report presents the results of five newly diagnosed Graves' hyperthyroid patients who were given 500 mg ipodate daily for 23 to 35 wks. Mean baseline serum T3, T4 and rT3 were 780 ng/dl, 25.4 ug/d1 and 118 ng/dl, respectively. One day after the first dose of ipodate, serum T3 decreased by 62% (P<0.005) and stayed within the normal range throughout the treatment. The serum T4 concentration decreased by 20% (P=0.09) at 24 h, 35% at 3 d(P<0.02) and 54% (P<0.005) at 21 d. Subsequently serum T4 was 41–65% lower than baseline throughout the study; it was within the normal range in four patients from 10 wks of treatment on. Serum rT3 increased at 24 h following the first dose of ipodate (118% above baseline, P<0.05 and remained elevated (97–109%) for 10 wks and then gradually decreased to baseline level. A significant decrease of resting pulse rate and marked gain in body weight (11±2.4 1b) were observed in all patients. Following the discontinuation of ipodate, thyroid radioiodine uptake in four patients was not different from baseline value: baseline, 74 ±6%; 7 d 66±8%; 14 d 71±7%; 28 d 69±7%. The fifth patient's RAI uptake Fell to 12–16% (vs. baseline value of 48%) from 7–28 d after the end of a 26-wk course of ipodate. In conclusion: (1) long term use (for 23–35 wks) of ipodate for the treatment of Graves' hyperthyroidism is clinically feasible; and (2) RAI uptake returns to baseline level as early as 7 d following the discontinuation of ipodate.

The effect of counting system deadtime on thyroid uptake measurements.

Equations are derived and the results of numerical calculations shown that illustrate the effect of counting system deadtime on measured thyroid uptake of radioiodine. It is predicted that the observed uptake is higher than the true uptake due to system deadtime. This is shown for both paralyzing and nonparalyzing deadtime. The effect of increasing the administered activity is shown to increase the measured uptake, in a manner predicted by the paralyzable and nonparalyzable deadtime models.

Reappraisal of the 3,5,3'-triiodothyronine-suppression test in the prediction of long term outcome of antithyroid drug therapy in patients with hyperthyroid Graves' disease.

Thyroidal suppressibility by exogenous T3 in terms of both radioiodine uptake (RAIU) and serum T4 was evaluated in 115 hyperthyroid patients treated with methimazole for 2 yr and followed for an additional 2 yr to study the rate of recurrence. Various other serum parameters including serum thyroglobulin concentrations, thyroid autoantibody, and TSH receptor antibody titers, and thyroidal responses to TRH-induced TSH elevation were also determined. After 2 yr of methimazole therapy, thyroidal RAIU was not suppressible (RAIU less than 12%/4 h was defined as suppressible) in 50 of 115 patients (group I). Of 65 patients with suppressible thyroid RAIU, serum T4 was significantly reduced (less than 60% of pre-T3 level) by T3 administration in only 43 patients (group III) but not in the remainder (group II). Antithyroid drug therapy was discontinued in the group II and III patients, and 7 of the patients had recurrence of hyperthyroidism within 2 yr of follow-up. All of them were from group II. The thyroidal response to TSH was greater in group III patients than in group II patients. During antithyroid drug therapy, decrease of microsomal antibody titer was more likely to occur in group III patients than in those of group II. Serum thyroglobulin concentrations were uniformly normal in treated patients irrespective of T3 suppressibility. TSH receptor antibody was positive in all 13 untreated patients with Graves' disease but was negative in treated patients regardless of their T3 suppressibility. Measurement of both thyroidal RAIU and serum T4 after administration of T3 improves the reliability of T3-suppression testing as a predictor of the remission of Graves' disease.

Autoimmune granulomatous thyroiditis in inbred mice: resemblance to subacute (de Quervain's) thyroiditis in man.

Mice in various inbred strains were immunized with mouse thyroglobulin emulsified in Freund's complete adjuvant. Granulomatous thyroid lesions were observed only in RF and SJL mice. These lesions were studied ultrastructurally and showed similarities with subacute (de Quervain's) thyroiditis in man. Thyroid function tests, e.g., the concentration of serum thyroxine and thyroid radioiodine uptake showed similarities between these two diseases. Such findings have not been previously described in experimental thyroiditis.

Control of goitre in lambs by injection of ewes with iodized poppy seed oil

The value of a single injection of 1 ml of iodized poppy seed oil in ewes was examined to prevent goitre in their lambs in an iodine deficient area in northern Tasmania. Control of goitre was achieved for only two years as assessed by thyroidal radio-iodine uptake in the ewe and histological changes in the lamb's thyroid. On a group basis the slope of the radio-iodine uptake curve in ewes was found to give an accurate reflection of the animals' iodine status as shown by the lambs' thyroid histology. The treatment had no effect on liveweight gain or fleece growth in lambs, but in the year after the treatment the ewes had a 6% increase in fleece weight.

Pituitary-thyroid feedback regulation in patients with Graves' disease during antithyroid drug therapy.

In an attempt to study the mode of normalization of thyroid function in patients with Graves' disease, a study was made on 140 patients with Graves' disease who were eumetabolic after appropriate therapy with antithyroid drugs for more than 9 months. T3 administration failed to suppress thyroidal radioiodine uptake and serum T4 in patients with TRH-unresponsive TSH secretion. In addition, exogenous TSH failed to elevate serum levels of T4 and T3. In patients with TRH-responsive pituitaries, T3 administration uniformly made serum TSH undetectable but produced various effects (unsuppressible, partially suppressible, and suppressible) on radioiodine uptake and serum T4. The magnitude of suppression of radioiodine uptake paralleled that of serum T4. In patients with unsuppressible or partially suppressible thyroids, exogenous and endogenous TSH were less effective in elevating serum T4 and T3. In patients with suppressible thyroids, T3 administration depressed radioiodine uptake and serum T4; the magnitudes of depression were comparable to those found in normal subjects. Exogenous and endogenous TSH elevated serum T4 and T3 in patients with suppressible thyroids. Here again, the magnitudes of elevation were comparable to those found in the normal subjects. The serum T3 to T4 ratio was high before treatment, but decreased significantly during antithyroid drug therapy. The magnitude of decrease was roughly proportional to the degree of T3 suppressibility.

Long-acting thyroid stimulator (LATS) and long acting thyroid stimulator protector (LATS-P) in untreated thyrotoxicosis.

The prevalence of serum LATS and LATS-P in untreated Graves' disease has been studied in eighty-three patients with thyroid overactivity; twelve (14%) were found to have significant levels of LATs and LATS-P whilst fifty-nine (72%) had significant levels of LATS-P alone. Twelve (14%) had neither activity. There was a very wide range in both activities. LATS was invariably found in association with a significantly greater concentration of LATS-P. There was no correlation between LATS-P and thyroid mass, as estimated from scintiscanning, thyroidal radioiodine uptake at 4 and 48 h, total serum T4 and total serum T3. Neither LATS nor LATS-P were detected in eleven patients with toxic multinodular goitre nor four with solitary toxic adenoma.