RESUMEN

This investigation addresses the interaction of insulin (INS) and glucocorticoid (GC) signaling in the hepatic regulation of tryptophan oxygenase (TO) enzyme activity in the rat. Male Wistar rats (200-250 g b.w) received an injection of the different doses of INS (10, 25, 50, 70 and 100 microg/200 g b.w., i.p.) and were used for experiments 3 h and 18 h after INS administration. This study shows that maximum of TO activity was found at dose of 50 microg of INS with peak increases observed at 3 h and 18 h after injection of INS, while INS had no effect on TO activity in adrenalectomized rats. The analysis of INS effects on glucocorticoid receptor-complex (GC/GR complex) stability shows that complexes from INS-treated rats are less stable than those from control animals. In addition, INS-stimulated stability of glucocorticoid receptor (GR) protein was significantly increased from the controls. Furthermore, the results show that GC/GR complexes from INS-treated rats could be activated and accumulated at higher rate in cell nuclei of control animals. These data support the involvement of INS in modulation of GC signaling pathway which mediates, in part, the activity of TO.

Asunto(s)

Insulina/fisiología , Hígado/enzimología , Receptores de Glucocorticoides/metabolismo , Transducción de Señal/fisiología , Triptófano Oxigenasa/metabolismo , Análisis de Varianza , Animales , Relación Dosis-Respuesta a Droga , Insulina/administración & dosificación , Masculino , Ratas , Ratas Wistar , Estadísticas no Paramétricas , Factores de Tiempo

RESUMEN

We used rat hepatic and uterine tissues to examine the impact of estradiol (E2) on insulin (INS) signaling. Ovariectomized (OVX) female Wistar rats were treated with E2 (20 microg/kg b.wt., i.p.) and used for the experiment 6h after E2 administration. To highlight E2 effects on tyrosine phosphorylation of INS receptor (IR) and INS receptor substrates (IRSs) and IRSs association with p85 subunit of phosphatidylinositol 3-kinase (PI3-K) in the context of INS signaling, E2-treated OVX rats were also injected with INS (20 IU, i.p.), 30 min before the experiment. Treatment with E2 did not change the levels of plasma INS and glucose (Glu). However, it significantly decreased the free fatty acid (FFA) level and increased uterine weight. Furthermore, the results show that E2 had no effect on the content of hepatic IR protein, but significantly increased IR protein content in the uterus and decreased IR tyrosine phosphorylation in both the liver and uterus. Compared to the control, hepatic IRS-1 and IRS-2 were significantly decreased and increased, respectively, after E2 treatment. Protein content of both molecules, IRS-1 and IRS-2, was increased in uterine tissue after E2 administration. Protein content of the p85 subunit of PI3-K and that of protein kinase B (Akt) were increased in the uterus, with no changes in the liver. The results suggest that E2 treatment induces tissue-specific changes in INS signaling. The consequences of E2 treatment on INS signaling molecules are more apparent in the uterus, but their physiological relevance for INS action is probably greater in the liver.

Asunto(s)

Estradiol/farmacología , Insulina/fisiología , Útero/efectos de los fármacos , Animales , Glucemia/análisis , Ácidos Grasos no Esterificados/sangre , Femenino , Insulina/sangre , Hígado/efectos de los fármacos , Hígado/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Ovariectomía , Ratas , Ratas Wistar , Receptor de Insulina/metabolismo , Transducción de Señal/efectos de los fármacos , Útero/anatomía & histología , Útero/metabolismo

RESUMEN

The effects of glucocorticoid excess on regulation of insulin receptors were investigated in dexamethasone-treated rats. Glucocorticoid excess was produced by administration of dexamethasone (0.5 mg/100 g b.w.) 30 min, 4, 12, 18, 24, 42 or 70 h before experiments. This treatment caused time-dependent changes of glucose and insulin concentration in blood, as well as in amounts of specific insulin binding and insulin receptors of liver cells and erythrocytes. The time intervals in which dexamethasone produced the increase in insulin concentration were accompanied with decrease in insulin binding to receptors in membranes of liver cells, while significant changes in insulin binding to receptors of erythrocytes were not observed under the same experimental conditions. The effect is maximal 18 and 42 h after dexamethasone treatment that increase insulin blood level by about 85% and 60%, respectively. Receptor analysis revealed that changes in specific binding of insulin could be due to significant changes in amount of binding sites on cell surface rather than to mild alteration in receptor affinity. These findings suggest that besides the changes in insulin level, the alterations in insulin receptor number and affinity may play a major role in the states of altered insulin sensitivity which accompany glucocorticoid excess.

Asunto(s)

Dexametasona/farmacología , Eritrocitos/efectos de los fármacos , Glucocorticoides/farmacología , Insulina/sangre , Hígado/efectos de los fármacos , Receptor de Insulina/metabolismo , Animales , Unión Competitiva , Glucemia/metabolismo , Membrana Celular/metabolismo , Células Cultivadas , Eritrocitos/metabolismo , Hígado/metabolismo , Masculino , Radioinmunoensayo , Ratas , Ratas Wistar , Factores de Tiempo

RESUMEN

The responses of liver glucocorticoid receptor (GR) and genes coding for a glucocorticoid-inducible tyrosine aminotransferase (TAT) and two acute-phase proteins (APP) [alpha2-macroglobulin (alpha2-M) and gamma-fibrinogen (Fb)] to changes in glucocorticoid (GC) and proinflammatory (AP) cytokine contents have been examined in rats after single or combined treatments with turpentine oil, dexamethasone (Dex) and adrenalectomy. Activation of two APP genes in turpentine-induced inflammation was accompanied by an increase in the level of GR mRNA and a preferential translocation of GR-GC complexes to the nucleoplasm, while the expression of TAT remained unaltered. Dex alone caused a decrease in the levels of GR and Fb mRNAs, activation of TAT and alpha2-M genes, a decrease in the affinity of hormone binding sites and redistribution of translocated GR-Dex complexes within the nuclei. Inflammation potentiated the effect which Dex alone exerted on the GR content and the number of GR binding sites but counteracted its influence on the affinity of GR binding sites and nuclear distribution of GR-Dex complexes. Adrenalectomy promoted a fall in TAT mRNA, no changes in the GR and Fb mRNA, a decrease in the affinity of GR hormone binding sites and redistribution of GR-hormone complexes within the nuclei. The AP cytokines released in response to inflammation exerted a counteracting effect on the adrenalectomy-induced changes in the affinity of hormone binding sites and nuclear distribution of GR-hormone complexes. They potentiated a fall of TAT mRNA but promoted full expression of the Fb gene. These results argue strongly for the influence of AP cytokines on the functional state of the GR and GC signaling pathways.

Asunto(s)

Adrenalectomía , Citocinas/farmacología , Dexametasona/farmacología , Fibrinógeno/biosíntesis , Regulación de la Expresión Génica/efectos de los fármacos , Glucocorticoides/farmacología , Hígado/efectos de los fármacos , Receptores de Glucocorticoides/biosíntesis , Tirosina Transaminasa/biosíntesis , alfa-Macroglobulinas/biosíntesis , Transporte Activo de Núcleo Celular/efectos de los fármacos , Animales , Regulación hacia Abajo/efectos de los fármacos , Inducción Enzimática/efectos de los fármacos , Fibrinógeno/genética , Inflamación/inducido químicamente , Inflamación/metabolismo , Irritantes/toxicidad , Hígado/metabolismo , Masculino , ARN Mensajero/biosíntesis , Ratas , Ratas Wistar , Receptores de Glucocorticoides/genética , Trementina/toxicidad , Tirosina Transaminasa/genética , Regulación hacia Arriba/efectos de los fármacos , alfa-Macroglobulinas/genética

RESUMEN

The dynamics and kinetics of thyroid hormone transport in the isolated rat heart were examined using the modified unidirectional paired tracer dilution method. The uptake of (125)I-thyroxine ((125)I-T(4)) and (125)I-triiodothyronine ((125)I-T(3)) from the extracellular space into heart cells was measured relative to the extracellular space marker (3)H-mannitol. The thyroid hormone maximal uptake was 54.4 % for (125)I-T(4) and 52.15 % for (125)I-T(3). The thyroid hormone net uptake was 25.69 % for (125)I-T(4) and 25.49 % for (125)I-T(3). Backflux from the intracellular space was 53.17 % for (125)I-T(4) and 61.59 % for (125)I-T(3). In the presence of unlabelled thyroid hormones, (125)I-T(4) and (125)I-T(3) maximal uptakes were reduced from 10.1 to 59.74 % and from 34.6 to 65.3 %, respectively, depending on the concentration of the unlabelled hormone, suggesting a saturable mechanism of the thyroid hormone uptake by the heart cells, with K(m(T4))= 105.46 microM and the maximal rate of (125)I-thyroid hormone flux from the extracellular space to heart cells (V(max(T4))) = 177.84 nM min(-1) for (125)I-T(4) uptake, and K(m(T3)) = 80.0 microM and V(max(T3)) = 118.5 nM min(-1) for (125)I-T(3) uptake. Experimental Physiology (2001) 86.1, 13-18.

Asunto(s)

Miocardio/metabolismo , Tiroxina/farmacocinética , Triyodotironina/farmacocinética , Animales , Transporte Biológico , Espacio Extracelular/metabolismo , Femenino , Técnicas In Vitro , Líquido Intracelular/metabolismo , Masculino , Miocardio/citología , Ratas , Ratas Wistar

RESUMEN

The glucocorticoid receptors in lymphocytes of patients treated with glucocorticoids after kidney transplantation have been studied in order to determine whether abnormalities in corticosteroid binding and trans-activation of steroid-receptor complexes, i.e., their translocation into nuclei, may contribute to the resistance of patients to glucocorticoid therapy. The patients were divided into two groups, according to graft stability: patients with stable graft function and those with chronic allograft rejection. The study revealed changes in both level and binding affinity of glucocorticoid receptors in peripheral blood lymphocytes from patients with chronic graft rejection, compared with control level, as well as with values of patients with stable graft function. These data indicate that sensitivity to glucocorticoids depends, at least in part, on the alterations of glucocorticoid receptors. The receptor translocation into nuclei indicates that unknown post-receptor events might also be involved in glucocorticoid resistance that seriously impair successive glucocorticoid therapy after organ transplantation. Further examination of glucocorticoid receptors in cases of organ transplantation seems warranted.

Asunto(s)

Trasplante de Riñón/fisiología , Linfocitos/metabolismo , Receptores de Glucocorticoides/metabolismo , Adulto , Estudios de Casos y Controles , Núcleo Celular/metabolismo , Citosol/metabolismo , Dexametasona/metabolismo , Femenino , Rechazo de Injerto/metabolismo , Humanos , Técnicas In Vitro , Cinética , Masculino , Persona de Mediana Edad

Asunto(s)

Miocardio/metabolismo , Triyodotironina/metabolismo , Animales , Capilares/metabolismo , Espacio Extracelular/metabolismo , Técnicas In Vitro , Radioisótopos de Yodo , Ratas , Triyodotironina/farmacocinética

Asunto(s)

Colforsina/farmacología , Receptores de Esteroides/efectos de los fármacos , Adenilil Ciclasas/metabolismo , Animales , Activación Enzimática/efectos de los fármacos , Estradiol/metabolismo , Femenino , Corazón/efectos de los fármacos , Técnicas In Vitro , Masculino , Miocardio/metabolismo , Fosforilación , Ratas , Receptores de Estrógenos/efectos de los fármacos , Receptores de Estrógenos/metabolismo , Receptores de Glucocorticoides/efectos de los fármacos , Receptores de Glucocorticoides/metabolismo , Receptores de Esteroides/metabolismo , Triamcinolona Acetonida/metabolismo

Asunto(s)

Melanoma Experimental/metabolismo , Receptores de Glucocorticoides/metabolismo , Animales , División Celular/efectos de los fármacos , Cortodoxona/farmacología , Melanoma Experimental/tratamiento farmacológico , Ratones , Triamcinolona Acetonida/metabolismo , Triamcinolona Acetonida/farmacología , Células Tumorales Cultivadas

RESUMEN

The technique of the universal film agarose electrophoresis has been used to detect biochemical characteristics of the body extract proteins in 3 different species and 2 genera of the pseudoscorpion family Neobisiidae. The migration rate of these proteins as well as their relative abundance for Neobisium carpaticum Beier, Neobisium macrodactylum (Daday) and Roncus pannonius Curcic, Dimitrijevic & Karamata, from Yugoslavia, were compared. Electrophoretic identifications of these species showed both species-specific and (probably) intergeneric differences. It is assumed that body protein electrophoresis can be also used: (a) to differentiate species in any stage of their life cycle, (b) to reveal the presence of sibling species, and to differentiate the taxonomic and evolutionary interrelations both in congeneric as well as in other, more distant taxa.

Asunto(s)

Arácnidos , Electroforesis en Gel de Agar , Proteínas/análisis , Animales , Arácnidos/clasificación , Arácnidos/metabolismo , Evolución Biológica , Clasificación , Escorpiones , Extractos de Tejidos/química

RESUMEN

The results obtained in the comparative study of age-related changes in TSH binding by thyroid tissues of euthyroid patients indicated that the content of high affinity binding sites of TSH receptors is not significantly decreased during aging, while the level of low affinity binding sites is increased in thyroid tissues of aged people. However, the dissociation constant of low affinity binding sites for TSH is significantly increased in thyroid tissues of old patients, compared with middle-aged people. Further investigation of functional characteristics of observed changes in TSH receptors and their binding parameters will provide a better understanding of the mechanism involved in the regulation of thyroid gland function during the aging.

RESUMEN

The parameters of 125I-bTSH binding to plasma membrane as well as serum thyroglobulin (Tg) level in 13 euthyroid females, suffering from scintigraphically functioning thyroid nodule, were investigated. Thyroid tissue samples of five euthyroid patients were obtained by surgical reintervention, which was done because of scintigraphically functioning nodular goitre relapse (Group 1). Data were compared with two control groups. One of them (Group 2) consisted of 5 euthyroid females in whom partial thyroidectomy was done because of solid functioning thyroid nodule. Long-term follow-up during postoperative period confirmed normal morphofunctional status in them. The second control (Group 3) is consisted of 3 patients suffering from goitre relapse now. The percent of specific 125I-bTSH binding and the affinity of its binding to plasma membranes from nodular goitre relapse were lower (2.05% +/- 0.82; Kd1: 0.56 +/- 0.34 10(-9) M; mean and S.D., resp.) than to the membranes obtained from surrounding perinodular tissue (0.32 +/- 0.89; Kd1: 0.20 +/- 0.77 10(-9) M, resp.). However, the level of high affinity TSH receptors in plasma membranes prepared from nodular goitre relapse was higher than that in perinodular, assumed to be normal tissue (11.21 +/- 0.87 fmol/mg prot. versus 6.29 +/- 2.24 fmol/mg prot., mean and S.D.). Plasma membranes obtained from goitre relapse were characterised by high total number of receptor and binding sites (N1 + N2) for TSH. In Group 1 and 3 elevated serum Tg levels were confirmed during follow-up period with no correlation with TSH, which characterises a normal physiological status of regulation.

Asunto(s)

Receptores de Tirotropina/análisis , Tiroglobulina/sangre , Nódulo Tiroideo/patología , Adulto , Membrana Celular/química , Membrana Celular/ultraestructura , Femenino , Humanos , Radioisótopos de Yodo , Persona de Mediana Edad , Recurrencia , Glándula Tiroides/patología , Glándula Tiroides/ultraestructura , Nódulo Tiroideo/epidemiología , Nódulo Tiroideo/ultraestructura

RESUMEN

TSH receptors were analyzed by equilibrium binding method of Scatchard in nodular and perinodular specimens surgically obtained from nine patients suffering from thyroid nodular goiter, which were clinically euthyroid. Among these patients, the group of those at "real risk" for reappearance of postoperative thyroid nodule in follow-up period was formed. The obtained results showed that there were no significant differences in specific 125I-bTSH binding between perinodular (assumed to be normal by PH analysis) and nodular tissues. The level of high affinity receptors was higher in perinodular than nodular specimens, while low affinity binding sites were increased in nodular tissue. Decreased level of high affinity and increased content of low affinity binding sites were observed in perinodular compared to nodular specimens obtained from patients of "real risk" group. These results give evidences for real risk of postoperative compensatory hypertrophy and thyroid goiter relapse in follow-up during long-term period.

Asunto(s)

Bocio Nodular/diagnóstico , Receptores de Tirotropina/análisis , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Ensayo de Unión Radioligante

RESUMEN

Disturbances in the glucocorticoid hormone serum level lead to dramatic, frequently lethal changes in mammalian organism (Addison's disease, Cushing's syndrome). Hypofunction of adrenal glands (hypocorticism) was simulated by bilateral adrenalectomy of male Wistar rats. Changes in the liver cell glucocorticoid receptor (GR) content were followed throughout 2 hrs to 8 days in the postoperative period, by the quantitative Western blot method and by the synthetic steroid equilibrium binding method of Scatchard. The results of our measurements showed: 1, 1.5 to 2 fold increase in the rat liver GR protein of adrenalectomized animals in respect to the appropriate controls. 2. the increase in the GR protein occurs already 2 hours after the operation and remains at the increased, plateau values throughout the time period studied. It is suggested that the liver GR level may be regulated by the negative feed back mechanism. The raised GR level in adrenalectomy may be a functional adaptation to the low hormone conditions.

Asunto(s)

Hígado/metabolismo , Receptores de Glucocorticoides/análisis , Insuficiencia Suprarrenal/metabolismo , Adrenalectomía , Animales , Western Blotting , Masculino , Ratas , Ratas Wistar

RESUMEN

The investigation of insulin effects on the glucocorticoid receptor (GR) in cytosol fraction of rat liver has been done in order to bring about more evidence on the interaction of these hormones in the regulation of metabolic processes. The experiments were performed with male Wistar rats intraperitoneally injected by 25 micrograms of insulin/100g body weight 3 or 18 hours before analysis. The obtained results show that insulin induces time dependent changes, in both, the level and functional properties of GR. The significant increase in the binding activity and receptor content was observed in both analysed time intervals of insulin treatment, while these increases were higher after 18 hours of insulin administration. These evidences suggest that mechanisms of cooperative effects of insulin and glucocorticoid on regulation of cell function involve the modulation of hormone signals transmission through increase in level and/or functionality of receptor proteins.

Asunto(s)

Insulina/farmacología , Hígado/metabolismo , Receptores de Glucocorticoides/análisis , Animales , Western Blotting , Masculino , Ratas , Ratas Wistar

RESUMEN

Phosphorylation of immunopurified chicken oviduct progesterone receptor (PR) was studied in intact cells and under cell-free conditions. Cytosol PR was isolated by incubation with anti-PR monoclonal antibody alpha PR22 adsorbed to protein A-Sepharose and suspended in a reaction mixture containing 10 mM Mg2+, 0.1 mM [gamma-32P]ATP, and the catalytic subunit of cAMP-dependent protein kinase (cAMP-PK) from bovine heart. All three major proteins of avian PR (PR-A, 79 kDa; PR-B, 110 kDa; 90 kDa) incorporated 32P-radioactivity on serine residues. The phosphorylation reaction was inhibited by synthetic inhibitors of protein kinases, H-8 and 20-residue peptide IP20. A 40 degrees C preexposure of PR oligomer increased phosphorylation of the 90-kDa protein, known to be a heat-shock protein (hsp-90). The extent of the phosphorylation reaction was temperature-dependent as the 32P-incorporation into PR-A and PR-B increased gradually, showing a maximum at 37 degrees C. Multiple phosphopeptides (4-7) were resolved by two-dimensional electrophoresis chromatography following cleavage of 32P-labeled peptides with trypsin. Both A and B forms of receptor showed similar phosphorylation patterns with B receptor digestion exhibiting two to three additional peptides. Under physiological conditions, preincubation of oviduct mince with forskolin, a regulator of intracellular cAMP levels, caused a greater extent of phosphorylation of PR-A and PR-B proteins. The results of this study demonstrate that chicken oviduct PR is an excellent substrate for the action of cAMP-PK in vitro and that this enzyme may be a physiological regulator of progesterone action in the oviduct.

Asunto(s)

Oviductos/metabolismo , Proteínas Quinasas/metabolismo , Receptores de Progesterona/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Western Blotting , Cationes Bivalentes/farmacología , Pollos , Citosol/metabolismo , Electroforesis en Gel Bidimensional , Electroforesis en Gel de Poliacrilamida , Femenino , Peso Molecular , Fosfatos/metabolismo , Radioisótopos de Fósforo , Fosforilación , Receptores de Progesterona/aislamiento & purificación

RESUMEN

The presence, affinity, binding capacity, structure and function of receptors for estrogen (ER), progesterone (PR) and glucocorticoid (GR) were investigated in 24 autologous pairs of control and neoplastic kidney tissues of patients with endemic (Balkan) nephropathy. In control tissue, all the three steroid receptors were absent in 20.8% and present in 25.0% of samples, whereas in malignant tissues the percentage of negative samples increased to 37.5% and that of positive ones decreased to 20.8%. Ten patients had identical receptors in both, control and cancer tissues. Due to malignant transformation nine patients lost one or more receptors, while five patients acquired them. Wide ranges of values were obtained when evaluating receptor affinity (Kd) and binding capacity (N). The structure and function of steroid receptors were investigated by determining the sedimentation coefficients (S) of steroid-receptor complexes before and after the activation. The unactivated GR-complex (8 S) was detected in two of control samples only, whereas in the remaining control tissues, as well as in malignant tissues only the activated form (4 S) was found regardless of the activation. PR and ER complexes were detected at 4 S region only. These results show that in endemic nephropathy the structure of steroid receptors may be altered often in both, non malignant and malignant kidney tissue, suggesting that the analysis of receptor structure may be worthwhile for the prediction of the success of eventual hormone therapy.

Asunto(s)

Nefropatía de los Balcanes/patología , Neoplasias Renales/ultraestructura , Riñón/ultraestructura , Receptores de Estrógenos/análisis , Receptores de Glucocorticoides/análisis , Receptores de Progesterona/análisis , Anciano , Nefropatía de los Balcanes/epidemiología , Nefropatía de los Balcanes/etiología , Femenino , Humanos , Riñón/química , Neoplasias Renales/química , Masculino , Persona de Mediana Edad , Receptores de Estrógenos/fisiología , Receptores de Glucocorticoides/fisiología , Receptores de Progesterona/fisiología , Esteroides/fisiología , Yugoslavia/epidemiología

RESUMEN

Tests were performed of the effects of the Somatostatin (SMS) upon the concentration of Insulin, Glucagon and STH, as well as of the effects of SMS upon the specific binding of the insulin to the receptors. The tests were carried out on eight insulin-independent diabetics, and five healthy volunteers. The tests were made with placebo, followed by 100 ug of the analogue SMS 201-995, known under the name of Sandostatin. Blood specimens for determining all parameters mentioned above were taken at 9 a.m., 3 p.m., 9 p.m., and 3 a.m. (09 h, 15 h, 21, and 03 h). The goal of the tests was to determine whether the SMS had any effect upon the glucoregulation, and at which level changes take place. In the group of healthy volunteers, a considerable decrease of insulin took place six hours after the administration of STH, and the decrease of the glucagon was especially marked, tending to increase again after six hours, while the specific binding of the insulin to the receptors, and the number of receptors were decreased six hours following the administration of the SMS when compared with the placebo, and without tending to reach the previous levels until 3 a.m. (03 h). In insulin-independent diabetics, the SMS leads to a considerable drop of concentrations of Insulin, Glucagon, STH and to a specific binding of the insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Diabetes Mellitus Tipo 2/metabolismo , Insulina/metabolismo , Receptor de Insulina/metabolismo , Somatostatina/farmacología , Glucagón/metabolismo , Hormona del Crecimiento/metabolismo , Humanos

RESUMEN

TSH receptors in plasma membranes of thyroid nodular and perinodular tissue and the concentration of thyroid hormones and thyroglobulin in serum were estimated in patients with Hashimoto's thyroiditis (HT) and in six persons with scintigraphically cold thyroid nodules (AFN). In perinodular tissue of HT patients specific binding of 125I-bTSH was found to be significantly decreased (1.50 +/- 0.13%; mean +/- S.E.) as compared with AFN patients (2.79 +/- 0.53%), whereas any significant difference in hormone binding to nodular tissues between both examined groups was not detected. Scatchard analysis of TSH binding revealed two kinds of binding sites for both thyroid tissues of all examined patients. The capacity of high affinity binding sites in both thyroid tissues of HT patients was found to be decreased (3.92 +/- 0.86 fmol/mg protein in nodular tissue and 5.93 +/- 1.16 fmol/mg protein in perinodular tissue) in comparison with these tissues of AFN patients (18.80 +/- 18.36 and 32.24 +/- 33.38, respectively). Any differences in dissociation constant and capacity of low affinity binding sites between analysed groups were not observed. Serum TSH levels of HT patients were higher than these in AFN patients and were not significantly changed after surgical treatment. Any difference in triiodothyronine (T3) levels between analysed groups was not detected, while the concentration of thyroxine (T4) was lower in HT than in AFN and significantly decreased after the excision of thyroid gland. Thyroglobulin levels were significantly changed after surgical treatment in both analysed groups.

Asunto(s)

Receptores de Tirotropina/metabolismo , Tiroiditis Autoinmune/metabolismo , Tiroxina/metabolismo , Triyodotironina/metabolismo , Adulto , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Femenino , Humanos , Persona de Mediana Edad , Radioinmunoensayo , Glándula Tiroides/patología , Glándula Tiroides/ultraestructura , Tiroiditis Autoinmune/patología , Tirotropina/metabolismo

RESUMEN

TSH receptors of plasma membrane fractions of human cold thyroid adenoma and perinodular thyroid tissues (PTT), assumed by pathohistological analysis to be normal, were examined. In perinodular thyroid tissues (PTT) obtained by partial thyroidectomy from twelve euthyroid female patients 125I-TSH binding (as determined by equilibrium binding analysis on particulate plasma membrane preparations) was found to be significantly increased as compared with scintigraphically cold thyroid nodular tissues (CTN). In all examined thyroid tissues Scatchard analysis of TSH binding revealed two kinds of binding sites: these with high affinity showed a significantly increased dissociation constant (Kd1), while these with low affinity showed a decreased dissociation constant (Kd2) in PTT as compared with CTN. The capacity of low affinity binding sites in PTT was found to be decreased in comparison with CTN tissues. These results suggest that the changes in affinity of TSH receptors sites as well as iodine deficiency of thyroid tissues may be an important events in functional status of analysed perinodular and cold nodular thyroid tissues.

Asunto(s)

Adenoma/metabolismo , Receptores de Tirotropina/metabolismo , Neoplasias de la Tiroides/metabolismo , Tirotropina/metabolismo , Adenoma/patología , Adulto , Femenino , Humanos , Membranas/metabolismo , Persona de Mediana Edad , Neoplasias de la Tiroides/patología