Triiodothyronine suppresses humoral immunity but not T-cell-mediated immune response in incubating female eiders (Somateria mollissima)

Immunity is believed to share limited resources with other physiological functions and this may partly account for the fitness costs of reproduction. Previous studies have shown that the acquired immunity of female common eiders (Somateria mollissima) is suppressed during the incubation fast. To save energy, triiodothyronine (T3) is adaptively decreased during fasting in most bird species, despite T3 levels are maintained throughout incubation in female eiders. However, the relationship between thyroid hormones and the immune system is not fully understood. The current study aimed to determine the endocrine mechanisms that underlie immunosuppression in incubating female eiders. ..

Profiles of Cortisol, Triiodothyronine, Thyroxine and Neutrophil/Lymphocyte Ratio as Stress Indicators in Swamp Buffaloes 15 Days Post-Transportation

Transportation may cause stress that affects livestock\u27s health. This research was conducted to observe the effect of transportation on the profiles of blood cortisol, triiodothyronine (T3), thyroxine (T4) and neutrophil/lymphocyte (N/L) ratio as stress indicators during 15 days post-transportation. Four females swamp buffaloes, 2-yr-old were used in this research. The animals were transported using an open truck, along 15 kilometers distance for 2 h. During acclimatization, the animals were fed grass twice a day and access to water ad libitum. Blood was collected at the time of arrival and everyday for 15 d post-transportation. Cortisol, T3 and T4were analyzed using Radioimmunoassay (RIA) method. Blood smears were also prepared and stained with Giemsa for leukocyte differential counts. Results showed a significant relation (P<0.05) between transport and an increase in cortisol and T4 level on day-1 post-transportation compared to the normal levels. The level of T3 was also increased on day-3 post-transportation. Total leukocyte counts were 8.91-18.83×10³/μL. Neutrophil, eosinophil, monocyte, and lymphocyte counts were 4.87-10.41×10³/μL, 0.66-1.75×10³/μL, 0.11-0.58×10³/μL, and 2.98-6.21×10³/μL, respectively. N/L ratio was 1.23-3.49 with >1.5 in average throughout the period of the research. It is concluded that transportation causes stress and therefore changes metabolic process

Thyroxine treatment in patients with symptoms of hypothyroidism but thyroid function tests within the reference range: randomised double blind placebo controlled crossover trial

OBJECTIVES: To determine whether thyroxine treatment is effective in patients with symptoms of hypothyroidism but with thyroid function tests within the reference range, and to investigate the effect of thyroxine treatment on psychological and physical wellbeing in healthy participants. DESIGN: Randomised double blind placebo controlled crossover trial. SETTING: Outpatient clinic in a general hospital. Participants: 25 patients with symptoms of hypothyroidism who had thyroid function tests within the reference range, and 19 controls. Methods: Participants were given thyroxine 100 microgram or placebo to take once a day for 12 weeks. Washout period was six weeks. They were then given the other to take once a day for 12 weeks. All participants were assessed physiologically and psychologically at baseline and on completion of each phase. MAIN OUTCOME MEASURES: Thyroid function tests, measures of cognitive function and of psychological and physical wellbeing. RESULTS: 22 patients and 19 healthy controls completed the study. At baseline, patients' scores on 9 out of 15 psychological measures were impaired when compared with controls. Patients showed a significantly greater response to placebo than controls in 3 out of 15 psychological measures. Healthy participants had significantly lower scores for vitality when taking thyroxine compared to placebo (mean (SD) 60 (17) v 73 (16), P<0.01). However, patients' scores from psychological tests when taking thyroxine were no different from those when taking placebo except for a poorer performance on one visual reproduction test when taking thyroxine. Serum concentrations of free thyroxine increased and those of thyroid stimulating hormone decreased in patients and controls while they were taking thyroxine, confirming compliance with treatment. Although serum concentrations of free triiodothyronine increased in patients and controls taking thyroxine, the difference between the response to placebo and to thyroxine was significant only in the controls. CONCLUSIONS: Thyroxine was no more effective than placebo in improving cognitive function and psychological wellbeing in patients with symptoms of hypothyroidism but thyroid function tests within the reference range. Thyroxine did not improve cognitive function and psychological wellbeing in healthy participants

Prognostic value of thyroid hormone levels in patients evaluated for liver transplantation

The thyroid hormones T4, T3, rT3 and TSH were assayed in 134 adult patients evaluated and accepted as potential liver transplant candidates at the Universty of Pittsburgh from March, 1981 to December, 1983. The subsequent course of these patients was evaluated with respect to the levels of these hormones obtained at the time of acceptance for transplantation. T4 levels were increased significantly while their T3 levels were reduced (both p < 0.01) in those who survived and were discharged home as compared to either those who died waiting to be transplanted or died following the procedure. As a result, the ratio of T3/T4 was reduced markedly (p < 0.01) in those who were transplanted and survived as compared to those not transplanted or dying following transplantation. Importantly, the rT3 levels clearly separated (p < 0.01) those who would die prior to transplantation from those who would survive to be transplanted. Finally, the ratio rT3/T3 even more clearly separates those who will die prior to transplantation (p < 0.01) from the other two groups. These data suggest that thyroid hormone levels, particularly rT3 levels, might be useful in setting priorities for which patients referred for a transplantation evaluation should be accepted into the program and in determining who among accepted patients should be operated upon in preference to others also accepted and waiting to be transplanted. Copyright © 1985 American Association for the Study of Liver Disease

The Pecularities of Correlation Between Insulin Resistance, Carbohydrate and Lipid Metabolism Indices in Patients with Graves'disease

Aim. The number of patients with endocrine disorders in the world, in particular, Graves' disease is continuously increasing. Recent studies have determined the fact of insulin resistance in thyroid disorders. On the one hand, numerous researches prove correlation of hypothyroidism with arterial hypertension, ischaemic heart disease and lipid metabolism disorder, on the other – carbohydrate metabolism disorder and hyper-sympathicotonia are closely associated with hyperthyroidism. The subject of the research was to study the correlation of insulin resistance, lipid and carbohydrate metabolism indices in patients with Graves'disease.Material and Methods. During the study 53 (37 female and 16 male) patients with Graves' disease with noticed IR have been examined. At the beginning, after 3– and 6-months thyreostatic therapy with insulin sensitizers (metformin or pioglitazone) the following investigations have been performed: assessing thyroid-stimulating hormone levels, free thyroxine and triiodothyronine; assessing glycated haemoglobin, glucose, C-peptide and fasting insulin as primary IR markers; calculating НОМА-IR index for analysing tissue sensitivity to insulin; calculating НОМА-β index for evaluating the functional capacity of β-cells of islets of Langerhans; measuring Caro indices to monitor hyperinsulinemia, measuring total cholesterol level, low-density lipoproteins, very-low-density lipoproteins, high-density lipoproteins , triglycerides, for analysing IR in relation to lipid metabolism.Results. The research results found out that free thyroid hormones and thyroid-stimulating hormone are closely related to lipid metabolism. Thus, thyroid-stimulating hormone was characterized as having direct correlation with low-density lipoproteins, while the free thyroxine inversely correlated with total cholesterol, low-density lipoproteins, and high-density lipoproteins. The free triiodothyronine negatively correlated with high-density lipoproteins. The research has also determined the direct correlation between insulin and free thyroxine, as well as free triiodothyronine in patients with diffuse toxic goitre.Conclusions. The study proves the presence of insulin resistance in patients with Graves' disease that generates interest to further study of the changes in insulin sensitivity, relation of insulin resistance to thyroid-stimulating hormone, thyroid hormones and looking for the ways to correct these disorders

Thyroid hormones correlate with field metabolic rate in ponies, Equus ferus caballus

Acknowledgments The authors thank Jürgen Dörl for technical help and for taking care of the animals and Peter Thompson for technical assistance with the doubly labelled water analysis. Funding The study was supported by a grant from the German Research Foundation (DFG;GE 704/13-1).Peer reviewedPublisher PD

Thyroid-hormone therapy and thyroid cancer: a reassessment.

Experimental studies and clinical data have demonstrated that thyroid-cell proliferation is dependent on thyroid-stimulating hormone (TSH), thereby providing the rationale for TSH suppression as a treatment for differentiated thyroid cancer. Several reports have shown that hormone-suppressive treatment with the L-enantiomer of tetraiodothyronine (L-T(4)) benefits high-risk thyroid cancer patients by decreasing progression and recurrence rates, and cancer-related mortality. Evidence suggests, however, that complex regulatory mechanisms (including both TSH-dependent and TSH-independent pathways) are involved in thyroid-cell regulation. Indeed, no significant improvement has been obtained by suppressing TSH in patients with low-risk thyroid cancer. Moreover, TSH suppression implies a state of subclinical thyrotoxicosis. In low-risk patients, the goal of L-T(4) treatment is therefore to obtain a TSH level in the normal range (0.5-2.5 mU/l). Only selected patients with high-risk papillary and follicular thyroid cancer require long-term TSH-suppressive doses of L-T(4). In these patients, careful monitoring is necessary to avoid undesirable effects on bone and heart