Thyroid disease with monoclonal (immunoglobulin G lambda) antibody to triiodothyronine and thyroxine.

A man with previous Graves' disease spontaneously developed hypothyroidism. He became euthyroid with T4 therapy, but developed inappropriately elevated serum levels of T3 and, to a lesser extent, T4. Gel filtration analysis (Sephadex G-150) of serum trace-labeled with [125I]T3 revealed binding to a high molecular weight fraction, distinct from normal T3-binding proteins.

A rapid standardized enzyme immunoassay for autoantibodies to thyroglobulin.

A rapid, specific, standardized, objective and sensitive quantitative enzyme immunoassay (ELISA) procedure has been developed for the detection of human autoantibodies to thyroglobulin. It involves three ten minute incubations, with the positive control serum adjusted to yield an absorbance of approximately 1.00.

The pituitary-thyroid axis after hemithyroidectomy in euthyroid man.

The pathogenesis of euthyroid goiter is assumed to be TSH dependent, but most studies have not demonstrated elevation of serum TSH. To elucidate the early events involved in thyroid growth, we studied thyroid function in eight euthyroid patients subjected to hemithyroidectomy for solitary cold nodules preoperatively and 2, 15, 60, and 90 days and 36 months, postoperatively. Although within the euthyroid range, serum T4 decreased at 30 days and thereafter up to 90 days (P less than 0.

Control of puberty in female rats: the effect of PTU-induced hypothyroidism and systematic undernutrition.

Sprague-Dawley rats were fed Purina Lab Chow with or without propylthiouracil (PTU), 0.001%, 0.01% or 0.

Hemoglobin A2 in hyperthyroidism.

Erythrocyte hemoglobin A2 (Hb A2) was quantitated in 28 hyperthyroid patients prior to antithyroid therapy and at intervals during therapy. Fetal hemoglobin (Hb F) levels and red cell mean corpuscular volume (MCV) were also monitored. Before therapy, Hb A2 was significantly elevated (mean +/- SD, 3.

Similar serum concentrations of thyroid hormones in two geographically separate populations on disparate iodine intake.

Serum thyroid hormones were measured in Montreal, Canada (urinary iodine 446 +/- 164 micrograms/day) and Zagreb, Yugoslavia (urinary iodine 108 +/- 32 microgram/day). The serum concentrations of thyroxine and triiodothyronine in the two populations were almost identical. We conclude that dietary iodine, within accepted normal limits, is not a factor in determining serum thyroid hormone levels.

Metabolism of monoamines and diamines in hyperthyroid and hypothyroid rats.

The in vivo rates of catabolism of 14C-labelled pentylamine, ethylamine, putrescine, and cadaverine were studied in thyroidectomized rats and others made hyperthyroid by the daily administration of 0.2 mg of L-thyroxine per kilogram for 20--21 days. Hyperthyroid rats metabolized the monoamines at an accelerated rate; thyroidectomized animals oxidized pentylamine at a reduced rate.

Enhanced thyroxine metabolism and high uptake goiters in rats after a single dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Nine days after treatment of rats with a single dose (25 microgram/kg) of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the 1 h biliary excretion of [125I]-thyroxine (T4) was increased 4-fold and the [125I]T4 bile:plasma ratio and the biliary clearance rate of plasma [125I]T4 were increased 10-fold. The proportion of biliary 125I present as T4-glucuronide was larger in TCDD-treated rats. Unexpectedly, TCDD did not influence the 30 min biliary excretion of [125I]triiodothyronine (T3), the [125I]T3 bile:plasma ratio, and the biliary clearance rate of plasma [125I]T3.

Elevated serum concentrations of thyroxine-binding globulin and caeruloplasmin in methadone-maintained patients.

Patients on a methadone-maintenance program had high serum concentrations of thyroxine-binding globulin. This resulted in elevated serum thyroxine and triiodothyronine levels and low triiodothyronine uptake values. Their free thyroxine index was normal, as was serum thyroxine and triiodothyronine when related to thyroxine-binding globulin concentration.

Goitres in rats fed polychlorinated biphenyls.

Rats fed a polychlorinated biphenyl (PCB) mixture in a high- or low-iodine diet (HID or LID respectively) for 15 days had thyroid enlargement, low serum thyroxine (T4), and high serum thyrotropin concentrations. Although binding of thyroid hormones to serum proteins was reduced in PCB-fed animals, the free T4 index (reflecting free T4 in serum) was less in these rats. Both serum triiodothyronine (T3) and the free T3 index were elevated in rats fed PCB in HID.

Minimal effects of free fatty acids on the competitive protein-binding assay of serum thyroxine on reusable Sephadex columns.

In rats; following oral administration of cream and intravenous heparin, plasma free fatty acids and triiodothyronine Sephadex uptake were elevated. Simultaneously apparent serum thyroxine, measured by the Tetrasorb-E kit, was increased, but not when measured using reusable Sephadex columns. Addition of oleate to a human serum albumin solution or to human serum produced similar effects; appreciable rises in apparent thyroxine were noted in the kit assay but only minor changes occurred when Sephadex columns were used.

A simple ligand-binding assay for thyroxine-binding globulin on reusable Sephadex columns.

A method for the assay of thyroxine-binding globulin on reusable Sephadex G-25 (fine) columns is described. It depends upon elution by diluted iodothyronine-free serum of protein-bound [125 I]thyroxine from the columns under conditions where binding to thyroxine-binding prealbumin and albumin are abolished. It is simple, rapid and precise and permits determinations in large numbers of samples.

Alterations in thyroxine metabolism produced by cutaneous application of microscope immersion oil: effects due to polychlorinated biphenyls.

A 30% solution of a polychlorinated biphenyl (PCB) mixture or a microscope immersion oil containing 34% PCB, when applied to the skin of rats, led to substantial increases in the biliary excretion of intravenously injected [125I]thyroxine (T4) in bile: plasma 125I ratios, in the biliary clearance rate of plasma [125I]T4, and in bile flow. Both PCB preparations also elevated liver weight, thyroid 125I uptake, and Sephadex uptake of [125I]triiodothyronine (T3), and depressed serum T4 concentrations; serum T3 levels were unaltered by the PCB solution or by the immersion oil containing PCB. PCB, either in mineral or immersion oil, reduced the free T4 index (serum T4 X fraction Sephadex T3 uptake), indicating a probable reduction in the concentration of free T4 in serum; the free T3 index, on the other hand, was elevated in PCB-treated rats.

Polychlorinated biphenyl-induced modification of lymphocyte response to plant mitogens in rats.

In PCB-treated rats total white cell and differential counts and lymphocyte proliferative response to PWM were unaltered. The lymphocyte response to PHA was increased in treated animals.

Assay of serum thyroxine by competitive protein binding: reuse of disposable sephadex columns.

A method for the assay of total serum thyroxine on reusable Sephadex G-25 fine columns, obtained from the Ames Tetralute kit, and competitive protein binding with TBG is described. The columns are regenerated with diluted plasma and may be used for at least 3 months. The procedure is rapid and simple and requires no extraction, centrifugation or evaporation.

Enchanced in vitro hepatic glucuronidation of thyroxine in rats following cutaneous application or ingestion of polychlorinated biphenyls.

In rats four daily skin application of a 30% solution of a polychlorinated biphenyl (PCB) mixture in mineral oil or of a microscope immersion oil, containing 34% PCB, led to increases in liver weight, protein concentration of the 10 000 X g supernatant fluid of liver homogenates and the in vitro glucuronidation of thyroxine (T4) by the supernatant fluid, whether related to liver weight or to protein concentration in the reaction mixture. Similar effects occurred after feeding 250 ppm (mg/kg) of PCB in either Purina chow or a low-iodine diet for 11 days. It is concluded that increased hepatic T4 glucuronidation contributes to the enhanced biliary excretion of T4 previously observed in PCB-treated rats.

Ehanced biliary thyroxine excretion in rats treated with pregnenolone-16alpha-carbonitrile.

Normal rats were treated with pregnenolone- 16alpha - carbonitrile (PCN) 10 mg/100 g by stomach tube twice daily for 3 days. In these animals the biliary excretion of intravenously injected 125I-thyroxine (T4) was enhanced and the bile: plasma 125I ratio (B/P ratio) and the biliary clearance rate of plasma 125I-T4 was increased. Normal rats were treated with PCN for 3 days and homozygous Gunn rats for 13 days.

On the mechanism of polychlorinated biphenyl-induced hypobilirubinaemia.

Treatment of normal rats with a polychlorinated biphenyl mixture of DDT increased liver microsomal protein concentration. Hepatic microsomal bilirubin UDP-glucuronyltransferase activity was elevated in the DDT-treated, but not in the polychlorinated biphenyl-treated rats. In contrast polychlorinated biphenyl, but not DDT, reduced serum bilirubin concentrations in jaundiced Gunn rats, as did sulphadiazine; sulphonamides compete with bilirubin for binding sites on plasma albumin.

[Thyroid pigments in Gunn rats].

The structural and histochemical characteristics of the thyroid pigment in homozygous Gunn rats were examined. The pigment occurs in the form of numerous yellow granules in the cytoplasm of the follicular cells. The focal depositions of the pigment were also seen in the central part of the luminal colloid.

[Effect of pregnenolone-16 alpha-carbonitrile on the activity of the rat thyroid gland and anterior pituitary].

PCN, in daily doses of 20 mg/100 g per body weight exerted a marked stimulative effect on the rat thyroid. It was also found that the uptake of radioiodine in animals receiving PCN, was increased. Chromatographic investigations have shown that in PCN treated animals the biosynthesis of thyroid hormones was accelerated.

Enhanced thyroxine metabolism following cutaneous application of microscope immersion oil.

Microscope immersion oil, applied to the skin of rats or injected intraperitoneally, led to a substantial increase in the biliary excretion of intravenously injected 125-I-thyroxine (T4), elevated the bile: plasma 125-I ratio, enhanced the biliary clearance rate of plasma 125-I-T-4 and increased the proportion of biliary 125-I present as T-4-glucuronide. Immersion oil applied to the skin was at least as effective as injected intraperitoneally. Skin application also elevated bile flow, liver weight, thyroid 131-I uptake and Sephadex uptake of serum 125-I-triiodothyronine (indicating reduced binding of thyroid hormone to serum proteins) and depressed serum T-4 concentrations.