scholarly journals Transthyretin Regulates Thyroid Hormone Levels in the Choroid Plexus, But Not in the Brain Parenchyma: Study in a Transthyretin-Null Mouse Model*

Endocrinology ◽  
2000 ◽  
Vol 141 (9) ◽  
pp. 3267-3272 ◽  
Author(s):  
Joana Almeida Palha ◽  
Rui Fernandes ◽  
Gabriella Morreale de Escobar ◽  
Vasso Episkopou ◽  
Max Gottesman ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Mouse Model ◽  
Choroid Plexus ◽  
Brain Parenchyma ◽  
Null Mouse ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
The Brain

Bulbospinal serotonergic activity during changes in thyroid status

1998 ◽  
Vol 76 (12) ◽  
pp. 1120-1131 ◽  
Author(s):  
William N Henley ◽  
Linda L Bellush ◽  
Marc Tressler
Keyword(s):  
Thyroid Hormone ◽  
Primary Hypothyroidism ◽  
Glycemic Status ◽  
Thyroid Status ◽  
Hormone Levels ◽  
Serotonergic Activity ◽  
Thyroid Hormone Levels ◽  
The Brain ◽  
Circulating Levels ◽  
Very High

A three-part study explored the basis for an interaction between changes in thyroid status and bulbospinal serotonin (5HT) metabolism. In experiment 1, three well-characterized models of primary hypothyroidism were all accompanied by significant increases in 5HT metabolism. In experiment 2, circulating thyroid hormone levels were experimentally varied from very low methimazole (Meth) treatment to very high (T3 implants: 2.5, 5.0, or 7.5 mg triiodothyronine). As in experiment 1, Meth led to elevated 5HT. Hyperthyroidism was accompanied by significant reductions in 5HT, while urinary norepinephrine excretion paralleled 5HT. In experiment 3, rats were subjected to Meth either 2 weeks before or after induction of diabetes with streptozotocin (Stz). Meth prevented Stz-associated reductions in 5HT and attenuated development of hyperphagia. Meth could not reverse established Stz-associated reduction in 5HT or hyperphagia, although both were slightly attenuated. Thus, although the first two experiments argue for a simple inverse relationship between circulating thyroid hormone levels and 5HT in the brain, experiment 3 demonstrated that Stz-associated decrements in 5HT could not be reversed by subsequent lowering of circulating thyroid hormone. Nor did accompanying measurements indicate that glycemic status or circulating levels of leptin were important predictors of 5HT. Thus the interaction between thyroid hormones and 5HT is both more subtle and more complex than previously thought.Key words: hypothyroidism, hyperthyroidism, serotonin, diabetes mellitus.

Film autoradiography identifies unique features of [125I]3,3'5'-(reverse) triiodothyronine transport from blood to brain

1994 ◽  
Vol 72 (1) ◽  
pp. 380-391 ◽  
Author(s):  
L. Y. Cheng ◽  
L. V. Outterbridge ◽  
N. D. Covatta ◽  
D. A. Martens ◽  
J. T. Gordon ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Choroid Plexus ◽  
Intravenous Administration ◽  
Binding Protein ◽  
Circumventricular Organs ◽  
Brain Parenchyma ◽  
Retinol Binding Protein ◽  
High Affinity ◽  
Reverse Triiodothyronine ◽  
The Brain

1. Steady-state iodothyronine profiles in plasma are composed of thyroid gland-synthesized hormones (mainly thyroxine) and tissue iodothyronine metabolites (mainly triiodothyronine and reverse triiodothyronine) that have entered the bloodstream. The hormones circulate in noncovalently bound complexes with a panoply of carrier proteins. Transthyretin (TTR), the major high-affinity thyroid hormone binding protein in rat plasma, is formed in the liver. It is also actively and independently synthesized in choroid plexus, where its function as a chaperone of thyroid hormones from bloodstream to cerebrospinal fluid (CSF) is undergoing close scrutiny by several groups of investigators. Because TTR has high-affinity binding sites for both thyroxine and retinol binding protein, its potential role as a mediator of combined thyroid hormone and retinoic acid availability in brain is of further interest. 2. While they are in the free state relative to their binding proteins, iodothyronines in the cerebral circulation are putatively subject to transport across both the blood-brain barrier (BBB) and choroid plexus CSF barrier (CSFB) before entering the brain. Previous autoradiographic studies had already indicated that after intravenous administration the transport mechanisms governing thyroxine and triiodothyronine entry into brain were probably similar, whereas those for reverse triiodothyronine were very different, although the basis for the difference was not established at that time. Intense labeling seen over brain ventricles after intravenous administration of all three iodothyronines suggested that all were subject to transport across the CSFB. 3. To evaluate the role of the BBB and CSFB in determining iodothyronine access to brain parenchyma, autoradiograms prepared after intravenous administration of [125I]-labeled hormones (revealing results of transport across both barriers) were compared with those prepared after intrathecal (icv) hormone injection (reflecting only their capacity to penetrate into the brain after successfully navigating the CSFB). 4. Those studies revealed that thyroxine and triiodothyronine were mainly transported across the BBB. They shared with reverse triiodothyronine a generally similar, limited pattern of penetration from CSF into the brain, with circumventricular organs likely to be the main recipients of iodothyronines (with or without retinol) transported across the CSFB. 5. Analysis of all of the images obtained after intravenous and icv hormone administration clarified the basis for the unique distribution of intravenously injected reverse triiodothyronine. The hormone is excluded by the BBB but may be subject to limited penetration into brain parenchyma via the CSF. 6. Overall the observations single out reverse triiodothyronine as the iodothyronine showing the most distinctive as well as the most limited pattern of transport from blood to brain.(ABSTRACT TRUNCATED AT 400 WORDS)

Evaluation of Positive Inotropic Drug Effects on Thyroid Hormone Levels after Open Heart Surgery

2015 ◽  
Vol 16 (2) ◽  
pp. 78
Author(s):  
Umit Kervan ◽  
Anil Ozen ◽  
Utku Unal ◽  
Irfan Tasoglu ◽  
Mahmut Mustafa Ulas ◽  
...  
Keyword(s):  
Drug Therapy ◽  
Thyroid Hormone ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Open Heart ◽  
Inotropic Drug ◽  
Hormone Levels ◽  
Inotropic Drugs ◽  
Positive Inotropic Drug ◽  
Thyroid Hormone Levels

<p><b>Objective:</b> The aim of this study was to examine the effects of positive inotropic drugs, including adrenaline, dopamine, and dobutamine on thyroid hormone levels following open heart surgery.</p><p><b>Methods:</b> We analyzed free thyroid hormones (FT3 and FT4) and thyroid-stimulating hormones (TSH) in 200 consecutive patients undergoing open heart surgery. Patients were divided into 5 groups according to the inotropic drug administration as follows: Group A (n = 46) received dopamine alone; Group B (n = 40), dopamine and dobutamine; Group C (n = 36), dopamine, dobutamine, and adrenaline; Group D (n = 32), adrenaline alone; and Group E (n = 46), placebo. Procedural factors affecting thyroid hormones were recorded and included cardiopulmonary bypass (CPB) time, cross-clamping time, degree of hypothermia, and the duration and doses of positive inotropic drugs. Blood samples for hormone assays were collected before initiation of inotropic drug therapy (baseline) and postoperatively at 24, 72, and 120 hours after drug therapy.</p><p><b>Results:</b> FT3, FT4, and TSH levels at baseline were similar in all groups. Although there was a trend showing very slight increases in thyroid hormone levels from baseline to the 24th, 72nd, and 120th postoperative hours after drug therapy, these changes were not significant, and there were also no significant differences between the groups. There was also no significant statistical difference in CPB time, cross-clamping time, degree of hypothermia, and duration and doses of positive inotropic drugs between groups.</p><p><b>Conclusion:</b> Although thyroid hormone levels were affected by positive inotropic drug usage after open heart surgery, this effect was not significant and thyroid hormone levels remained within normal ranges.</p>

Predictive value of thyroxine for prognosis in pediatric septic shock: a prospective observational study

2020 ◽  
Vol 33 (5) ◽  
pp. 653-659
Author(s):  
Jia Song ◽  
Yun Cui ◽  
Chunxia Wang ◽  
Jiaying Dou ◽  
Huijie Miao ◽  
...  
Keyword(s):  
Septic Shock ◽  
Thyroid Hormone ◽  
Observational Study ◽  
Hospital Mortality ◽  
Predictive Value ◽  
Prospective Observational Study ◽  
Threshold Value ◽  
Nonthyroidal Illness ◽  
Hormone Levels ◽  
Thyroid Hormone Levels

AbstractBackgroundThyroid hormone plays an important role in the adaptation of metabolic function to critically ill. The relationship between thyroid hormone levels and the outcomes of septic shock is still unclear. The aim of this study was to assess the predictive value of thyroid hormone for prognosis in pediatric septic shock.MethodsWe performed a prospective observational study in a pediatric intensive care unit (PICU). Patients with septic shock were enrolled from August 2017 to July 2019. Clinical and laboratory indexes were collected, and thyroid hormone levels were measured on PICU admission.ResultsNinety-three patients who fulfilled the inclusion criteria were enrolled in this study. The incidence of nonthyroidal illness syndrome (NTIS) was 87.09% (81/93) in patients with septic shock. Multivariate logistic regression analysis showed that T4 level was independently associated with in-hospital mortality in patients with septic shock (OR: 0.965, 95% CI: 0.937–0.993, p = 0.017). The area under receiver operating characteristic (ROC) curve (AUC) for T4 was 0.762 (95% CI: 0.655–0.869). The cutoff threshold value of 58.71 nmol/L for T4 offered a sensitivity of 61.54% and a specificity of 85.07%, and patients with T4 < 58.71 nmol/L showed high mortality (60.0%). Moreover, T4 levels were negatively associated with the pediatric risk of mortality III scores (PRISM III), lactate (Lac) level in septic shock children.ConclusionsNonthyroidal illness syndrome is common in pediatric septic shock. T4 is an independent predictor for in-hospital mortality, and patients with T4 < 58.71 nmol/L on PICU admission could be with a risk of hospital mortality.

scholarly journals Thyroid Hormone Levels in Apparently Euthyroid Subjects with Essential Hypertension in a Tertiary Hospital in Nigeria

2013 ◽  
Vol 5 (01) ◽  
pp. 26-29 ◽  
Author(s):  
Abiodun Mathias Emokpae ◽  
Aliyu Abdu ◽  
Humphrey Benedo Osadolor
Keyword(s):  
Essential Hypertension ◽  
Thyroid Hormone ◽  
Medical Information ◽  
Young Patients ◽  
Thyroid Stimulating Hormone ◽  
Overt Hypothyroidism ◽  
Thyroid Disorder ◽  
Major Health Problem ◽  
Hormone Levels ◽  
Thyroid Hormone Levels

ABSTRACT Background: High blood pressure (BP) is a major health problem in Nigeria and the involvement of thyroid hormones in this condition has not been evaluated in this center. Objective: The objective of this study was to evaluate the proportion of patients with an essential hypertension who had abnormal thyroid hormone levels and the type of thyroid disorders commonly observed in this group of patients. Materials and Methods: A retrospective study of 94 patients (30 males, aged 30.4 ± 2 years and 64 females, aged 43.4 ± 1.3 years) with essential hypertension was carried out between January 2005 and December 2007. Demographic and other medical information were obtained from the health records. Analysis of laboratory results of triiodothyronine (T3), Thyroxine (T4), and thyroid stimulating hormone (TSH) were made. Results: Of the 94 patients evaluated, 26 (27.7%) had abnormal thyroid hormone levels, with 23.4% having hyperthyroidism, 4.3% had sub-clinical hypothyroidism and none had overt hypothyroidism. Of the 26 subjects with abnormal thyroid hormone levels, 18 (69.2%) were females while 8 (30.8%) were males. Out of the 18 female subjects with abnormal thyroid hormone levels, 16 had hyperthyroid levels while 2 had sub-clinical hypothyroid levels. Out of the 8 male patients, 6 had hyperthyroid hormone levels while 2 had sub-clinical hypothyroid levels. Conclusion: Thyroid hormone abnormalities are common in patients with essential hypertension. Hyperthyroidism was the most common thyroid disorder observed. Young patients presenting with essential hypertension should be screened for thyroid hormone abnormalities since they can best be managed by treating the underlying causes.

Sign in / Sign up

Export Citation Format

Share Document