TY - JOUR
T1 - Euthyroid hyperthyroxinemia and thyroxine-binding prealbumin excess in islet cell carcinoma
AU - Rajatanavin, Rajata
AU - Liberman, Claudio
AU - Lawrence, George D.
AU - D’arcangues, Catherine M.
AU - Young, Ruth A.
AU - Emerson, Charles H.
PY - 1985/7
Y1 - 1985/7
N2 - This manuscript describes euthyroid hyperthyroxinemia secondary to elevated serum T4-binding prealbumin (TBPA) concentrations in a patient with islet cell carcinoma and reports serum TBPA measurements in other patients with islet cell carcinoma. A 73-yr-old man with a 17-yr history of metastatic islet cell carcinoma was found to have hyperthyroxinemia. His total serum T4 concentration was 18.5 Mg/dl (normal, 5.5-11.5). Eight years previously, his serum T4 concentration was normal. His free T4 concentration, as determined by equilibrium dialysis, was 1.3 ng/dl (normal, 0.9-2.1). Serum T3, TSH, and T4-binding globulin (TBG) concentrations were normal, as was the TSH response to TRH administration. Polyacrylamide gel electrophoresis of the patient’s serum in the presence of tracer amounts of [125I]T4 revealed that, compared to normal sera, [125I]T4 binding to TBPA was increased from 30.0 ± 6.0% (mean ± SD) to 52.0%. The distribution of [125I]T3 amont albumin, TBG, and TBPA was normal in this electrophoretic procedure. The concentration of TBPA in the patient’s serum was 189 mg/dl. In contrast, the mean serum TBPA concentration in normal men was 40 ± 4 (mean ± SD) mg/dl, and that in normal women was 18 ± 4 mg/dl. Sera from the patient’s daughter, his brother, 2 sisters, and 2 male paternal cousins contained normal amounts of TBPA, ranging from 34-47 mg/dl in his male relatives and from 26-30 mg/dl in his female relatives. Serum free T4 index determinations in his relatives also were normal. Serum TBPA concentrations were determined in 14 additional patients with islet cell carcinoma. In 1 of these patients, a man with an insulinoma, serum TBPA was elevated (66 mg/dl). This patient’s serum T4 level was 7.3 Mg/dl, and his free T4 index was 7.0. These data and another study suggest that islet cell carcinoma may rarely produce a TBPA-like protein resulting in an elevated serum TBPA concentration. Markedly elevated serum TBPA is associated with euthyroid hyperthyroxinemia.
AB - This manuscript describes euthyroid hyperthyroxinemia secondary to elevated serum T4-binding prealbumin (TBPA) concentrations in a patient with islet cell carcinoma and reports serum TBPA measurements in other patients with islet cell carcinoma. A 73-yr-old man with a 17-yr history of metastatic islet cell carcinoma was found to have hyperthyroxinemia. His total serum T4 concentration was 18.5 Mg/dl (normal, 5.5-11.5). Eight years previously, his serum T4 concentration was normal. His free T4 concentration, as determined by equilibrium dialysis, was 1.3 ng/dl (normal, 0.9-2.1). Serum T3, TSH, and T4-binding globulin (TBG) concentrations were normal, as was the TSH response to TRH administration. Polyacrylamide gel electrophoresis of the patient’s serum in the presence of tracer amounts of [125I]T4 revealed that, compared to normal sera, [125I]T4 binding to TBPA was increased from 30.0 ± 6.0% (mean ± SD) to 52.0%. The distribution of [125I]T3 amont albumin, TBG, and TBPA was normal in this electrophoretic procedure. The concentration of TBPA in the patient’s serum was 189 mg/dl. In contrast, the mean serum TBPA concentration in normal men was 40 ± 4 (mean ± SD) mg/dl, and that in normal women was 18 ± 4 mg/dl. Sera from the patient’s daughter, his brother, 2 sisters, and 2 male paternal cousins contained normal amounts of TBPA, ranging from 34-47 mg/dl in his male relatives and from 26-30 mg/dl in his female relatives. Serum free T4 index determinations in his relatives also were normal. Serum TBPA concentrations were determined in 14 additional patients with islet cell carcinoma. In 1 of these patients, a man with an insulinoma, serum TBPA was elevated (66 mg/dl). This patient’s serum T4 level was 7.3 Mg/dl, and his free T4 index was 7.0. These data and another study suggest that islet cell carcinoma may rarely produce a TBPA-like protein resulting in an elevated serum TBPA concentration. Markedly elevated serum TBPA is associated with euthyroid hyperthyroxinemia.
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U2 - 10.1210/jcem-61-1-17
DO - 10.1210/jcem-61-1-17
M3 - Article
C2 - 2987291
AN - SCOPUS:0021810208
SN - 0021-972X
VL - 61
SP - 17
EP - 21
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
IS - 1
ER -