An abnormality of thyroid hormone secretion

An

Abnormality

of

Thyroid

Hormone

Secretion* ROBERT E . MACK, M .D ., KATHLEEN T . HART, PH .D ., DEA DRUE'r, M .s . and MARY ANNE BAUER, B .S . St . Louis, Missourt r is now well established that thyroxine is the I principal labeled thyroid hormone which can be recovered from the serums of patients given radioactive iodine, even when large doses of radioactive material are employed [1] . The occurrence of small quantities of triiodothyronine in human serum was first described by Gross and Pitt-Rivers [2] . In a similar study Benua et al . [3] found that when circulating 1131 labeled triiodothyronine was present, its concentration was greater than thyroxine only in the very early period following 1131 therapy . The purpose of this communication is to report the unusual finding of large quantities of triiodothyronine in the serum of a patient with thyroid carcinoma . This was demonstrated following the administration of three successive therapeutic doses of radioactive iodine . CASE REPORT A forty-eight year old man was transferred to the St . Louis Veterans Administration Hospital in April 1935 with the diagnosis of a tumor of the fourth lumbar vertebra . On physical examination a small nodule was noted in the isthmus of the thyroid gland . There was tenderness over the spine of the fourth lumbar vertebra . The basal metabolic rate was plus 48 . Roentgenographic examination of the lumbosacral spine revealed the presence of an osteolytic process involving the body and lamina of the fourth lumbar vertebra . In May 1955 a left hemithyroidectomy was performed with the pathologic diagnosis of well differentiated carcinoma of the thyroid gland . This was followed by a total thyroidectomy . Postoperatively, radioiodine studies revealed concentration of the radioactive material in the lumbar area and three 25 me . doses of P31 were administered over a period of several weeks . In November 1955 progressive spastic paralysis of the lower extremities developed in the patient which necessitated readmission to the St . Louis Veterans

Administration Hospital . His basal metabolic rate was plus 72, later plus 38 . The serum protein-bound iodine was 3 .4 pg . per cent . Roentgen therapy to the lower part of his back as well as 75 mc . of 1181 were administered without symptomatic relief. In January 1956 a decompression laminectomy was performed, and thyroid carcinoma was found in the excised fragments . Postoperatively the paraplegia regressed . On readmission to the hospital in November 1956, the only physical finding was a wasting away of the muscles of the lower extremities . There was no clinical evidence of hypothyroidism . The protein-bound iodine was 4 .1 pg . per cent . Following the administration of a tracer dose of 1131 the conversion ratio was 82 per cent . A scintigram of the neck region failed to demonstrate the presence of any radioactivity in the thyroid area . Scanning over the back revealed two concentrations of the radioactive material, one at the level of the second thoracic vertebra and another over the fourth lumbar vctcbra . One hundred and five millicuries of I131 were administered in November 1956, blood was obtained forty-eight hours later for the study of labeled thyroid hormone content . The patient was again admitted to the hospital in September 1957 after suffering a fracture of the neck of the left humerus in a fall . Physical findings were limited to pain and tenderness in the lumbar area and also at the fracture site . A roentgenogram of the left shoulder revealed the presence of a fracture of the neck of the humerus. There was nothing to suggest that this was a pathologic fracture. Tracer studies again demonstrated the concentrations of radioactive iodine in the same locations as on the previous hospital admission, but none at the fracture site . In September 1957, 130 me . of I" were administered and blood was obtained at twenty-four, forty-eight and seventy-two hour intervals for analysis of labeled hormone . The most recent admission to the St . Louis Veterans Administration Hospital was in June 1959 with the complaint of progressive loss of strength in the lower extremities . These changes were noticed about three months prior to this admission . The patient had not taken thyroid extract as had been recommended in

" From the St . Louis Veterans Administration Hospital and the Department of Internal Medicine, St . Louis University School of Medicine, St . Louis, Missouri . 323 FERROARS 1961

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Abnormality of Thyroid Hormone Secretion-Mack ei al .

FIG . 2 . Radioautographs of chromatograms of serum obtained twenty-four, forty-eight and seventy-two hours after the second therapeutic dose of I"' with the position of carriers indicated. FIO. 1 . A radioautograph of the chromatogram of serum obtained forty-eight hours after 1 11 therapy . Tx refers to carrier thyroxine and TIT to triiodothyronine .

September 1957 . Serum protein-bound iodine was 4 .1 pg. per cent . Following the administration of a tracer dose of 1 181 , the conversion ratio at forty-eight hours was 60 per cent . Scanning revealed two areas of radioactivity in the spine identical in location with those previously described . A 110 me . dose of 1131 was administered, serum being obtained twenty-four, forty-eight and seventy-two hours afterward for chromatographic analysis . Thyroid extract therapy was instituted several days later and the patient was discharged with instructions to return for re-evaluation in six weeks. METHODS OF STUDY

For the chromatographic studies carried out during the 1956 and 1957 hospital admissions the patient's serum was precipitated with trichloracetic acid and the precipitate extracted with butanol . The extracts were concentrated under vacuum and aliquots of each were chromatographed by the ascending method on Whatman No . 1 paper cut in tapered form [4] . The following two solvent systems were employed : (1) butanol-dioxane-ammonia [5], and (2) butanol-acetic acid-water [6] . Radioactivity on the strips was located by radioautography on no-screen x-ray film and by scanning with an automatic scintillation counter .

Thyroxine, triiodothyronine, c iodide and diiodotyrosine were similarly chromatographed with each aliquot of plasma extract. Spraying the strips with ninhydrin revealed the location of the former two . Iodide and diiodotyrosine were detected by spraying with ceric sulfate-arsenious acid reagent . The serum collected during the most recent hospital admission was acidified, extracted with butanol saturated with O .IN HC1 and the extract concentrated under vacuum . Chromatography of filter paper strips was carried out as before in butanol-dioxane-ammonia . Radioactivity and carrier thyroxine and triiodothyronine were located as already described . Two-dimensional chromatograms were also obtained for each serum sample using butanol-dioxane-ammonia followed by butanol-ammonia [7] . The location of radioactivity was compared to that of carrier thyroxine and triiodothyronine . RESULTS

The chromatograms of the patient's serum in the butanol-acetic acid-water system failed to disclose either mono- or diiodotyrosine . Figure 1 depicts the radioautograph of a chromatogram of the patient's serum obtained in November * The L-thyroxine and L-triiodothyronine used in this study were made available to us through the kindness of H . A. Klusek of Smith, Kline and French Laboratories, Philadelphia, Pennsylvania . AMERICAN JOURNAL OF MEDICINE

Abnormality of Thyroid Hormone Secretion-Mack et al .

325

totwo-dimensional chromatogram of the patient's serum forty-eight hours after the last time l"' therapy was given . Triiodothyronine is well separated from thyroxine . Fiu . 4. A

COMMENTS

Radioautograph of the patient's serum obtained after the most recent therapeutic dose of radioiodine . Most of the radioactivity is associated with thyroxine . Fm . 3 .

1956, forty-eight hours after radioiodine therapy . The location of the carrier thyroxine and triiodothyronine on the chromatogram is indicated by the markers . Although separation is not complete, most of the radioactivity is at a level corresponding to triiodothyronine . Analysis of this chromatogram by means of an automatic scanning counter demonstrated approximately 80 per cent of the total radioactivity associated with triiodothyronine . In Figure 2 are the radioautographs of chromatograms obtained following a second therapeutic dose of radioiodine ten months later . The strips represent samples of blood drawn at twenty-four, fortyeight and seventy-two hours . The concentrations of radioactivity at the level of thyroxine and of triiodothyronine appear approximately equal in each of the strips . In Figure 3 are radioautographs of chromatograms obtained following the most recent therapeutic dose . Two bands of radioactivity are seen which correspond to the thyroxine and triiodothyronine labels . Thetwodimensional chromatogram in Figure 4 clearly demonstrates thyroxine, triiodothyronine and iodide . FEBRUARY

1961

This patient is of particular interest in that a cuthyroid state has continued more than four years following total thyroidectomy . The finding of an elevated I 131 conversion ratio on two occasions is in marked contrast with the normal serum protein-bound iodine determinations . A somewhat analogous situation may he found in the low serum protein-bound iodine level of myxedematous patients maintained in a euthyroid state by triiodothyronine [8,9] . Other investigators [10,11] have noted artifacts with trichloracetic acid precipitated serum and in butanol-containing chromatographic systems, both of which were employed in the first two studies of this patient . Such artifacts have been shown to appear ahead of thyroxine, where one might expect to find triiodothyronine . The occurrence of a predominant radioactive serum component corresponding to triiodothyronine has been noted in three of nineteen patients studied in a similar fashion in our laboratory . In addition to the case reported herein, both of the other patients had had a total thyroidectomy for thyroid carcinoma and were receiving therapeutic I131 to eradicate residual thyroid tissue . The infrequent finding of this quantitatively abnormal serum coiiipunent in our series of patients argues against its being an artifact . In view of the clear identification of triiodothyronine on the more recently obtained two-dimensional chromatogram, it is

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Abnormality of Thyroid Hormone Secretion-Mack et al .

reasonable to conclude that this patient's metastatic lesions have persistently secreted large quantities of triiodothyronine . The explanation for the abnormal secretion of triiodothyroninc in our patient is obscure . Increased quantities of it have been found in the serums of hyperthyroid patients and in euthyroid persons following the administration of thyroid-stimulating hormone [12,13] . Rupp and his associates [14] have recently noted the occurrence of triiodothyronine as the only circulating thyroid hormone in a patient with a non-toxic goiter . They postulate an intrathyroidal enzyme defect leading either to the almost exclusive production or secretion of triiodothyronine . Since their patient also demonstrated an elevated 1 131 conversion ratio, a qualitatively similar enzymatic defect may exist in our patient . Inspection of the one-dimensional chromatograms demonstrates a progressive decrease in triiodothyronine and a corresponding increase of thyroxine with the administration of each therapeutic dose of 1131 . It is interesting to speculate that this change may represent an effect of radiation on the metastatic cells resulting in an anatomically and functionally more mature lesion . SUMMARY

A patient with thyroid carcinoma whose metastatic lesions have been demonstrated to secrete abnormally large amounts of triiodothyronine is described . It is suggested that this quantitative abnormality may result from an intracellular enzymatic defect in the metastasis . REFERENCES 1 . ROBBINS, J ., RALL, J . E ., BECKER, D. V . and RAwsoN, R . W . The nature of the serum iodine after large doses of I's' . J. Clin. Endotrinol ., 12 :856,1952 .

2 . GROss, J . and Psrr-RIVERS, R . The identification of 3 :5 :3'-l-triiodothyroninc in human plasma . Lancet, 262 : 439, 1952. 3 . BENUA, R. S ., Doavxs, B. M . and NINMER, A . Triiodothyronine in the serum of patients treated with radioactive iodine . Tr . Am . Loiter, A ., p . 216, 1955 . 4 . ALBRIGHT, E. C ., LARSON, F . C . and DElss, W. P . Single dimension chromatographic separation of thyroxin and triiodothyronine . Proc . Soc . Exper . Biol . & Med., 84 : 240, 1953 . 5 . Gauss, J ., LEBLOND, G. P., FRANKLIN, A . E . and QUASTEL, J . H . Presence of iodinated amino acids in unhydrolyzed thyroid and plasma . Science, 111 : 605, 1950 . 6 . RocHE, J., JuTaz, M ., LISSITZKV, S . and MICHEL, R . Chromatographie quantitative des asides amines iod6s radioactifs de la thyroglobuline marquee . Biochim . et biophys . acta, 7 : 257, 1951 . 7 . ROCHE, J., LISSITZSKV, S . and MICHEL, R . Characterization of iodohistidines in iodinated proteins (thyroglobulin and iodoglobulin) . Binchim- et biophys . acta, 8 : 339, 1952 . S . ASPER, S . P., JR ., SELENKOW, H. A . and PLAMONDON, C . A . A comparison of the metabolic activities of 3,5,3'-l-triiodothyronine and 1-thyroxin in myxcdema. Bull . Job" Hopkins Hasp ., 93 : 164, 1953 . 9 . STARR, P ., SNIPES, G . and LIEBIIOLD-SCIIDECK, R Biological effects of triiodothyroninc in human subjects . J. Clin . Endocrinol., 15 : 98, 1955 . 10 . ACLANn, J . D . Probable nature of an artifact in the paper chromatograph of thyroxine caused by trichlor acetic acid . Nature, 176 : 694, 1955 . 11 . OWEN, C. A ., JR ., McKENZIE, B. F . and ORVIs, A . An artifact in thyroxine chromatography using dioxane . J. Lab . & Clin . Med., 47 : 145, 1956 . 12 . BENUA, R. S . and DoEVNs, B . M . Iodinated compounds in the serum, disappearance of radioactive iodine from the thyroid and clinical response in patients treated with radioactive iodine . J. Clin . Endocrinol ., 15 : 118, 1955 . 13 . Hvnovrrz, J . D . and ARONS, W . L . Effect of thyrotropin on the pattern of thyroid hormones in plasma . J. Clin . Endocrinal ., 17 : 1332, 1957 . 14 . Run, J. J ., CHAVARRIA, C ., PASHKIS, K . E . and CHABLARIAN, E . The occurrence of triiodothyronine as the only circulating thyroid hormone . Ann . Int . Med., 51 : 359, 1959 .

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