Alterations in Thyroid Hormone Levels and Left Ventricular Contractility in Primary Hypothyroidism as a Consequence of Warming

1981 ◽  
Vol 60 (3) ◽  
pp. 27P-27P
Author(s):  
B. Northover ◽  
B. P. O'Malley ◽  
F. D. Rosenthal
1998 ◽  
Vol 76 (12) ◽  
pp. 1120-1131 ◽  
Author(s):  
William N Henley ◽  
Linda L Bellush ◽  
Marc Tressler

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.


2009 ◽  
Vol 62 (9-10) ◽  
pp. 407-411
Author(s):  
Radoslav Pejin ◽  
Nikola Curic ◽  
Branka Kovacev-Zavisic ◽  
Ljiljana Todorovic-Djilas

Introduction. The relation between thyroid hormones and bone metabolism markers in hyperthyroidism is well known. Earlier studies indicate the possibility of bone metabolism acceleration during the excessive replacement therapy with l-thyroxin in hypothyroid patients especially in one with other risk factors for bone metabolism impairment. This study evaluated the effect of physiological l-thyroxine treatment on bone metabolism in patient with primary hypothyroidism. Material and methods. In the study group of 30 hypothyroid patients individual thyroxine replacement was performed targeting euthyroid status. Bone and calcium metabolism parameters (osteocalcin-OC, alkaline phosphates-ALP, C-terminal cross-linking telopeptide type I-CL, parathormone-PTH, Ca, ionized Ca, P), thyroid hormone levels (T3, T4, TSH) were measured before treatment and when euthyroid status was achieved. Results and discussion. A significant treatment effect was observed for bone formation and resorption parameters before and during the therapy; OC (p=0.000024), CL (p=0.002648). Ionized calcium levels also showed significantly higher values in euthyroid status confirming bone metabolism acceleration during the l-thyroxine therapy (p= 0.020). Thus, calcium metabolism hormone regulators were not significantly different before and after the therapy; PTH (p=0.27). Thyroid hormone levels showed significant correlation with bone metabolism parameters before the therapy whereas this correlation was not found during therapy because of different individual l-thyroxine doses. Conclusion. It can be concluded that physiological doses of l-thyroxine therapy accelerate bone metabolism in hypothyroid patients. Thus, the argument against bone loss during physiological substitution is highly specific mutual correlation between bone formation and resorption parameters. These assumptions require further investigations in long term prospective studies in patients on replacement l-thyroxine therapy.


2019 ◽  
Vol 8 (5) ◽  
pp. R76-R90 ◽  
Author(s):  
Madalena von Hafe ◽  
João Sergio Neves ◽  
Catarina Vale ◽  
Marta Borges-Canha ◽  
Adelino Leite-Moreira

Thyroid hormones have a central role in cardiovascular homeostasis. In myocardium, these hormones stimulate both diastolic myocardial relaxation and systolic myocardial contraction, have a pro-angiogenic effect and an important role in extracellular matrix maintenance. Thyroid hormones modulate cardiac mitochondrial function. Dysfunction of thyroid axis impairs myocardial bioenergetic status. Both overt and subclinical hypothyroidism are associated with a higher incidence of coronary events and an increased risk of heart failure progression. Endothelial function is also impaired in hypothyroid state, with decreased nitric oxide-mediated vascular relaxation. In heart disease, particularly in ischemic heart disease, abnormalities in thyroid hormone levels are common and are an important factor to be considered. In fact, low thyroid hormone levels should be interpreted as a cardiovascular risk factor. Regarding ischemic heart disease, during the late post-myocardial infarction period, thyroid hormones modulate left ventricular structure, function and geometry. Dysfunction of thyroid axis might even be more prevalent in the referred condition since there is an upregulation of type 3 deiodinase in myocardium, producing a state of local cardiac hypothyroidism. In this focused review, we summarize the central pathophysiological and clinical links between altered thyroid function and ischemic heart disease. Finally, we highlight the potential benefits of thyroid hormone supplementation as a therapeutic target in ischemic heart disease.


1978 ◽  
Vol 133 (3) ◽  
pp. 211-218 ◽  
Author(s):  
D. G. McLarty ◽  
W. A. Ratcliffe ◽  
J. G. Ratcliffe ◽  
J. G. Shimmins ◽  
A. Goldberg

SummaryThe prevalence of abnormal serum total thyroxine (T4) and triiodothyronine (T3) concentrations were determined in 1,206 in-patients in two associated psychiatric hospitals. The biochemical pattern of primary hypothyroidism occurred in five females and one male (prevalence 0.5 per cent), but in only one patient was the diagnosis clinically obvious. Eight patients (all female) were clinically hyperthyroid (prevalence 0.7 per cent), of whom six were previously undiagnosed. There was no evidence that phenothiazines or benzodiazepine therapy had any significant effect on thyroid hormone levels. The small differences in thyroid hormone levels between psychiatric diagnostic groups could be explained by differences in age distribution.


2015 ◽  
Vol 16 (2) ◽  
pp. 78
Author(s):  
Umit Kervan ◽  
Anil Ozen ◽  
Utku Unal ◽  
Irfan Tasoglu ◽  
Mahmut Mustafa Ulas ◽  
...  

<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>


2019 ◽  
Vol 46 (5) ◽  
pp. 2137-2144
Author(s):  
Sahmin Lee ◽  
Seunghyun Choi ◽  
Sehwan Kim ◽  
Yeongjin Jeong ◽  
Kyusup Lee ◽  
...  

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