Long-acting Thyroid Stimulator Research Articles

The Effects of Lymphocytes, Sera and Long-Acting Thyroid Stimulator from Patients with Graves' Disease on Retrobular Fibroblasts

ABSTRACT Lymphocytes, both living and freeze-thawed, stimulated glycosaminoglycans (GAG) production and glucose utilization by monolayer fibroblast cultures derived from human retrobulbar connective tissue. Freeze-thawed lymphocytes from patients with Graves' disease, most of whom had active ophthalmopathy, were significantly (p < 0.05) more potent in this system than lymphocytes from normal subjects. The stimulating qualities of the lymphocytes could not be related to any clinical feature of the disease. Living lymphocytes from patients did not differ significantly from those of normal individuals in potency to stimulate the retrobulbar fibroblasts. Sera, including LATS containing sera, and IgG fractions of sera containing LATS produced changes in the cultures which were no different than those observed for comparable specimens from normal individuals. Graves' ophthalmopathy, in which accumulations of GAG play a prominent role, may develop from the interaction of lymphocytes and orbital connective tissue...

Circulating inhibitor of LATS: a bioassay artefact.

We previously reported (1) existence of a circulating inhibitor of the long-acting thyroid stimulator [LATS] based on demonstration of LATS activity in unconcentrated immunoglobulin G [IgG] fractions prepared from LATS-negative sera of hyperthyroid patients. The present report details a variety of subsequent studies which indicate that these initial findings were occasioned by a bioassay artefact.

Effects of long-acting thyroid stimulator on the reorganization into follicles of isolated thyroid cells and on the binding of radioiodinated thyrotropin to reassociated cells

Effects of long-acting thyroid stimulator on the reorganization into follicles of isolated thyroid cells and on the binding of radioiodinated thyrotropin to reassociated cells

Appearance of amine-containing mast cells in the mouse thyroid induced by the human long-acting thyroid stimulator (LATS).

The occurrence of mast cells in the mouse thyroid was examined by light and fluorescence microscopy after treatment of normal animals with human blood plasma, having high activity of the long—acting thyroid stimulator (LATS). Control animals were given LATS—negative human plasma, or a combination of LATS—positive human plasma and rabbit antibodies against human immunoglobulin G (anti—IgG). No, or very few, 5- HT- and histamine—storing mast cells were seen in thyroids of normal mice, while such cells were frequently seen in various extrathyroidal tissues. The same was true in animals treated twice daily for 1 week with LATS—negative plasma, or with LATS—positive plasma plus anti—IgG. In contrast, twice—daily injections for 1 week of strongly LATS—positive plasma promoted the appearance of numerous 5-HT- and histamine—containing mast cells within the thyroid. No apparent change was recorded in the number of extrathyroidal mast cells, in any of the experiments. As a similar intrathyroidal appearance of 5-HT—...

NEONATAL HYPERTHYROIDISM

SummaryNeonatal Graves disease, with frank cardiac failure and pronounced bilateral breast enlargement, is described in a premature infant female.Thyrotoxicosis, culminating rapidly in thyroid storm, was successfully treated by administration of Lugol's solution, digitalis and phenobarbital.The case is discussed in reference to the legitimacy of long‐acting thyroid stimulator (LATS) as the originator of neontal thyrotoxicosis.Although LATS could not be detected, the occurrence of gastric parietal cell antibodies in both mother and child yielded presumptive evidence for thyrotoxicosis as an autoimmune disease.

Identification of LATS as an antigen-antibody complex.

Since its detection in 1956 long-acting thyroid stimulator (LATS) has been discussed as the pathogenetic factor in Graves’ disease and its complications. It is defined as an IgG-globulin with the immunological and physico-chemical criteria of an autoantibody. The corresponding antigen could not be detected until now. There are two theories about the mechanism of action of LATS on the thyroid: The first holds that the biological activity results from the antigen-antibody reaction within the thyroid, the other that LATS is an antigen-antibody complex with a prolonged thyroid stimulating activity.

Effect of polyphloretin phosphate on the induction of thyroid hormone secretion by various thyroid stimulators.

The influence of polyphloretin phosphate (PPP), a presumed antagonist of prostaglandin, on the secretion of thyroid hormone was studied in 131I—injected, T4–suppressed mice treated with various thyroid—stimulating substances. Indices of response were the formation of colloid droplets and the increase in blood radioiodine (BRI) levels. Administration of PPP 5 min prior to thyrotrophin (TSH) or the long—acting thyroid stimulator (LATS) reduced both the colloid droplet formation and the BRI increments induced by these stimulators. On the other hand, the responses to prostaglandin E1; norepinephrine, 5–hydroxytryptamine, isoproterenol, and dibutyryl—cyclic adenosine–3'5'—monophosphate were either unimpaired or augmented by PPP. It is suggested that PPP selectively inhibits TSH— and LATS—stimulated secretion of thyroid hormone, by an action on specific receptor sites. (Endocrinology92: 1269, 1973)

Isoelectric focusing of long-acting thyroid stimulator immunoglobulin G.

Isoelectric focusing of long-acting thyroid stimulator immunoglobulin G [LATS-IgG] was used to determine the distribution of LATS activity among IgGs of various isoelectric points and to determine if isoelectric focusing techniques might yield LATS-IgG of increased biologic activity. LATS-IgG prepared from 16 LATS-positive sera was fractionated by isoelectric focusing [72 hr, 1200 V] using a 1% Ampholine solution, pH range 7.0 to 10.0. On the basis of absorbance at 280 nm, the effluent was gathered into 8 fractions. The 8 LATS-IgG subfractions and the parent IgG were tested in the same mouse bioassay. Following each of the 16 isoelectric focusing runs, maximal LATS activity was confined to one [6 instances] or two [10 instances] IgG subfractions [peak pi 8.99 ± 0.08 and 8.78 ± 0.09, respectively], with a 4- to 7-fold increase in LATS activity per mg protein compared to the parent IgG. However, of 12 LATS-negative Graves' disease IgGs submitted to isoelectric focusing, none of the IgG subfractions so deriv...

Chronic active hepatitis and Graves' disease.

Two young females who had chronic active hepatitis associated with Graves' disease are reported. Both patients had high circulating levels of immunoglobulin G and 1 had a monoclonal gammopathy which disappeared with steroid therapy. The other patient had exophthalmos and high circulating levels of long acting thyroid stimulator (LATS) which were paralleled by very high antibody titers to respiratory syncytial virus, herpes simplex, and echovirus 9. Both patients showed positive smooth muscle antibody and negative Australia antigen. In 1 case LATS and smooth muscle antibodies were found in the pleural fluid. Both patients had a wide variety of abnormal antibodies.

Cell-mediated immunity in Graves' disease and in Hashimoto's thyroiditis as shown by the demonstration of migration inhibition factor (MIF).

Demonstration of migration inhibition factor (MIF)3 is a generally, albeit not universally, accepted test for cell-mediated immunity. Peripheral leukocytes are allowed to migrate in either culture medium alone, or with various antigens. If the antigens are employed to which the lymphocytes are previously sensitized, the lymphocytes will then produce MIF, which causes inhibition of leukocyte migration. Leukocytes from patients with Graves' disease and Hashi moto's thyroiditis were studied; other subjects included a group of normal persons, patients with various other thyroid disorders, as well as a group of patients with auto-immune diseases. In the patients with Graves' disease, and Hashimoto's thyroiditis, MIF was found to be markedly positive to thyroid antigens, but not to control antigens. In patients with Graves' disease, treated with radioactive iodine, years earlier, MIF appeared to be lower. There was no correlation between the MIF results and the presence or titre of thyroid auto-antibodies and/or long-acting thyroid stimulator (LATS). These findings indicate a role for cell-mediated immunity, not only in Hashimoto's thyroiditis, but in Graves' disease as well.

Pretibial Myxedema and Nonthyrotoxic Thyroid Disease

Four patients had a distinct variant of exophthalmic goiter (Graves' disease) characterized by pretibial myxedema and nonthyrotoxic thyroid disease. A review of literature revealed 19 cases with similar findings. All were adults and two thirds were women. Exophthalmos and acropachy were present. One third were hypothyroid and the rest were euthyroid at the time the pretibial myxedema, exophthalmos, and acropachy developed. None had ever had signs or symptoms of hyperthyroidism. Long-acting thyroid stimulator (LATS) was present in all cases in which it was sought. Even though a hypermetabolic state was not present in these patients, the occurrence of dermopathy, opthalmopathy, and LATS furnished three of the four components of Graves' disease. Present evidence suggests that the thyroid disease in the patients, whether it be primary hypothyroidism or thyroiditis, is etiologically closely related to the diffuse toxic goiter of Graves' disease.

Adenosine 3′,5′-cyclic phosphate phosphodiesterase from bovine thyroid: Isolation and properties of a partially purified, soluble fraction

1. 1.|Adenosine 3′,5′-cyclic phosphate (cyclic AMP) phosphodiesterase was partially purified from a 10 000 × g supernate of bovine thyroid; the enzyme preparation so obtained was free of 5′-nucleotidase and deaminase activity and yielded [ 3H]-adenosine 5′-phosphate (AMP) as the end product of enzymatic hydrolysis of cyclic [ 3H]AMP. 2. 2.|Using an assay procedure that relied on physiologic substrate concentrations ( i.e confirming to known intracellular levels of cyclic AMP in thyroid), the partially purified thyroid phosphodiesterase was kinetically characterized and compared with a highly purified beef heart phosphodiesterase preparation. Double reciprocal plots of cyclic AMP hydrolysis yielded two apparent Michaelis constants: the lower in the 10 −6 M and the higher in the 10 −5 M range. Two apparent K m values were also obtained for Mg 2+ which was required for expression of maximal enzymatic activity. Other bivalent cations (Mn 2+, Co 2+, Ca 2+) activated the enzyme to a significantly lesser extent; Zn 2+ was stimulatory at 10 −4 M and inhibitory at ≥ 10 −3 M. 3. 3.|A number of cyclic nucleotides and acylated derivatives thereof interfered with the enzymatic hydrolysis of cyclic [ 3H]AMP to varying degrees; of these the mono- and dibutyryl derivatives of cyclic AMP were the most potent inhibitors. The inhibition was competitive in nature with K i values for dibutyryl cyclic AMP, N 6-monobutyryl cyclic AMP, and O 2′-monobutyryl cyclic AMP of 1.6·10 −4 M, 1.1·10 −4 M and 2.6·10 −5 M, respectively. 4. 4.|Methylxanthines and quazodine strongly inhibited thyroid phosphodiesterase whereas sulfonylureas were weakly inhibitory. 5. 5.|High concentrations of pituitary thyrotropin in vitro enhanced thyroid phosphodiesterase activity slightly while heat-inactivated thyrotropin, long-acting thyroid stimulator immunoglobulin G, and the prostaglandins E 2 and F 1 a were ineffective; prostaglandin E 1 was weakly inhibitory. The prostaglandin antagonists 7-oxa-13-prostynoic acid and polyphloretin phosphate effected significant inhibition of thyroid phosphodiesterase, possibly accounting for the agonist properties of these agents occasionally observed in vitro. 6. 6.|Upon complexing with a cyclic AMP-binding protein prepared from beef kidney, cyclic [ 3H]AMP became completely resistant to enzymatic breakdown by thyroidal phosphodiesterase.

The immunologic basis of Graves's disease.

Although many questions remain to be answered regarding the etiology of Graves's disease (toxic diffuse goiter), increasing evidence indicates that immune factors participate in its pathogenesis. Indeed, they may prove to be essential in the initiation of the disorder. As Werner and his colleagues note elsewhere in this issue, it has long been recognized that there is lymphocytic infiltration within the thyroid gland in Graves's disease; lymphocytosis, and enlargement of lymph nodes, thymus and spleen are also common. In addition, the finding of long-acting thyroid stimulator (LATS), which proved to be an immunoglobulin G (IgG), in the serum of many . . .

Purification and characterization of long-acting thyroid stimulator inhibiting factor from human thyroid tissues

Long-acting thyroid stimulator inhibiting factors were isolated from thyroid tissue extract by means of (NH 4) 2SO 4 fractionation and DEAE-column chromatography. Three fractions from DEAE column—F2, F6 and F7—contained the inhibitory activity. Fractions 6 and 7 (LIF-B) contained thyroglobulin. Fraction 2 (LIF-A) was further purified into three fractions by gel filtration on Sepharose 4B. A 320-fold concentration of the inhibitory activity was obtained in the second fraction (LIF-A-F2). Fractions 6 and 7 were pooled (LIF-B) and yielded four fractions on Sepharose 4B fractionation. Fractions 3 and 4 contained long-acting thyroid stimulator inhibiting factor activities of 62- and 58-fold enrichment when compared to the original thyroid homogenate. This step separated thyroglobulin from the inhibitory activity. The three (Sudan Black B-positive) fractions remained essentially at the point of application when paper electrophoresis was done at pH 8.6 and 12.0. By thin-layer chromatography four to five lipid components were extracted from these three fractions. The above data suggest the possible existence of multiple inhibitory factors which are lipoprotein in nature.

The binding of ( 3 H)thyrotropin and an 3 H-labeled exophthalmogenic factor by plasma membranes of retro-orbital tissue.

Plasma membranes of cells from retroorbital tissue have been prepared from the Harderian glands of guinea pigs and have been characterized as being reasonably free of other subcellular structures by electron microscopy and by enzyme-marker analyses. Both bovine thyrotropin and a proteolytic derivative of bovine thyrotropin with exophthalmogenic activity but without thyroid-stimulating activity specifically bind to these membranes. Gammaglobulin from the sera of patients with malignant exophthalmos increases the binding of both pituitary factors, whereas binding is not similarly increased by gammaglobulin from the sera of individuals who are not exophthalmic. The increased binding caused by the gammaglobulin from exophthalmic patients is the same whether the sera are positive or negative for the long-acting thyroid stimulator. Present binding experiments do not indicate a direct interaction between the gammaglobulin and the plasma membranes of the cells from Harderian glands. A mechanism for the pathogenesis of human exophthalmos is proposed on the basis of these data.

The long-acting thyroid stimulator and the result of I 131 treatment for thyrotoxicosis.

Summary: Serial assays of the long-acting thyroid stimulator (LATS) were performed in 93 patients with thyrotoxicosis before and after 5 mCi of l131LATS was related to the presence of exophthalmos initially but not to its progress after treatment. LATS was not related to the thyroid status 12 months after l131therapy by any means of analysis. The initial plasma protein bound iodine before treatment was correlated positively with continuing thyrotoxicosis at 12 months whereas thyroid size was only significantly related in the group with large (grade 3) goitres.

Effects of Long-Acting Thyroid Stimulator on Thyrotropin Stimulation of Adenyl Cyclase Activity in Thyroid Plasma Membranes

Both thyroid-stimulating hormone (TSH) and long-acting thyroid stimulator (LATS) stimulated adenyl cyclase activity in plasma membranes obtained from bovine thyroid glands. The stimulation induced by LATS was much less than that obtained with maximal amounts of TSH. LATS inhibited TSH stimulation of adenyl cyclase activity while an equivalent amount of normal human gamma-globulin did not influence basal or TSH-stimulated activity. The inhibition by LATS appeared to be noncompetitive and was greatest when the plasma membranes were initially exposed to LATS for 30 min at 0 degrees C before being incubated with TSH for 10 min at 37 degrees C. Inhibition could still be demonstrated when the plasma membranes were incubated for 30 min at 0 degrees C with TSH before the addition of LATS. Prolonging the period of incubation of plasma membranes with LATS from 30 to 60 min did not augment the stimulation of adenyl cyclase or increase the inhibition of the effect of TSH. Papain digests of LATS also increased adenyl cyclase activity of thyroid plasma membrane and inhibited the stimulation induced by TSH. The inhibitory effect of LATS was not completely specific for TSH and thyroid plasma membranes since glucagon stimulation of adenyl cyclase in hepatic plasma membranes was also inhibited, but to a lesser extent. In contrast to the results obtained with thyroid plasma membranes, LATS did not influence basal adenyl cyclase activity in hepatic plasma membranes. Furthermore equivalent amounts of normal human gamma-globulin also decreased glucagon stimulation of adenyl cyclase activity in plasma membranes obtained from liver. The present data suggest that LATS stimulation of adenyl cyclase in thyroid plasma membranes might be due to a change in the membrane configuration rather than binding to a specific receptor site. Such modification of the membrane structure could interfere with the binding of TSH to specific receptors or to the subsequent stimulation of adenyl cyclase. However, the results do not exclude the possibility that some component in the preparation other than LATS might be responsible for the inhibition of the stimulation by TSH.

Adenyl cyclase activity in the mouse thyroid gland.

SUMMARY The activation of adenyl cyclase in intact mouse thyroid glands was measured by the conversion of [3H]ATP to [3H]cyclic AMP. Untreated serum had an inhibitory effect. Human thyroid-stimulating hormone (TSH) and γG-globulin prepared from serum containing the long-acting thyroid stimulator (LATS), activated adenyl cyclase and the log-dose—response relationship did not deviate from parallelism. The rate of activation by LATS was slower and the peak response was delayed, compared with the response to TSH. The possible significance of this is discussed. Other hormones and neurotransmitters examined had no effect on thyroidal adenyl cyclase.

Discrepancy between inactivation by thyroid particulate fraction and thyroid stimulating activity of long-acting thyroid stimulator (LATS).

LATS is inactivated when incubated with human thyroid particulate fraction (HTP). This inactivation is presumed to be due to binding of LATS to the fraction. In the present investigation, we sought to determine whether binding to thyroid particulate fraction is related to the thyroid-stimulating activity of LATS, by comparing LATS inactivation by comparable quantities of human and murine thyroid particulate fraction (MTP) with that of chicks (CTP) whose thyroid glands have been shown not to be stimulated by LATS. HTP inactivated LATS markedly and regularly, while both MTP and CTP did so only slightly and erratically. On the other hand, intracellular colloid droplets were induced in vitro by LATS to a significant extent in murine as well as human thyroid tissue, while not in chick thyroid tissue. These findings suggest that thyroid-Stimulation by LATS is not necessarily accompanied by its inactivation and that inactivation of LATS in vitro is not due to the same binding which precedes thyroid activation.

Inactivation of long-acting thyroid stimulator in vivo.

SUMMARY The prolonged action of long-acting thyroid stimulator (LATS) in the McKenzie assay could be related to the slow clearance of LATS from the blood of assay mice. Injection of soluble thyroid extracts before or after LATS reduced the assay response. This corresponded with the inactivation of circulating LATS activity by the formation of a complex which was then rapidly removed from the blood.