Plasma homocysteine is decreased in the hypothyroid rat

2000 ◽  
Vol 78 (7) ◽  
pp. 565-570 ◽  
Author(s):  
René L Jacobs ◽  
Lori M Stead ◽  
Margaret E Brosnan ◽  
John T Brosnan
Keyword(s):  
Cardiovascular Disease ◽  
Thyroid Hormone ◽  
Independent Risk Factor ◽  
Hormone Replacement ◽  
Plasma Homocysteine ◽  
Total Plasma ◽  
Thyroid Hormone Replacement ◽  
Cystathionine Beta Synthase ◽  
Osmotic Pumps ◽  
Hypothyroid Patients

Recent clinical studies have indicated that plasma homocysteine was significantly increased in hypothyroid patients. Since hyperhomocysteinemia is an independent risk factor for cardiovascular disease we investigated homocysteine metabolism in hypothyroid rats. Hypothyroidism was induced in one study by addition of propylthiouracil (PTU) to the drinking water for 2 weeks. In a second study, thyroidectomized and sham-operated rats were used with thyroid hormone replacement via mini-osmotic pumps. Unlike the human hypothyroid patients, both groups of hypothyroid rats exhibited decreased total plasma homocysteine (30% in PTU rats, 50% in thyroidectomized rats) versus their respective controls. Thyroid replacement normalised homocysteine levels in the thyroidectomized rat. Increased activities of the hepatic trans-sulfuration enzymes were found in both models of hypothyroidism. These results provide a possible explanation for the decreased plasma homocysteine concentrations. The hypothyroid rat cannot be used as a model to study homocysteine metabolism in hypothyroid patients.Key words: homocysteine, cystathionine beta-synthase, cystathionine gamma-lyase, thyroid hormone.

Linear modulation of serum thyrotrophin by thyroid hormone treatment in hypothyroidism

1980 ◽  
Vol 95 (4) ◽  
pp. 472-478 ◽  
Author(s):  
A. Eugene Pekary ◽  
Jerome M. Hershman ◽  
Clark T. Sawin
Keyword(s):  
Thyroid Hormone ◽  
Hormone Replacement ◽  
Hormone Treatment ◽  
Significant Negative Correlation ◽  
Thyroid Hormone Replacement ◽  
Basal Serum ◽  
Thyroid Hormone Levels ◽  
Peak Versus ◽  
Hypothyroid Patients ◽  
Serum Tsh

Abstract. Basal serum TSH and the peak TSH response to a 500 μg TRH bolus were measured in 57 euthyroid and in 29 hypothyroid subjects either receiving graded thyroid hormone replacement or acutely removed from full replacement therapy. Serum TSH, total T4 and T3 were determined by sensitive radioimmunoassay methods. The peak versus basal TSH data for hypothyroid patients were linear within individuals. The regression slope of the peak versus basal TSH data for all hypothyroid subjects did not differ significantly from the corresponding slope for all euthyroid subjects. Basal and peak TSH versus T3 and T4 data for hypothyroid patients were also linear within each individual. Moreover, the regression of the basal TSH values averaged over the non-replacement to full replacement state against the TSH versus T3 slope had a significant negative correlation. This trend leads to an array of regression lines which average to the familiar hyperbolic relationship between thyrotrophin and thyroid hormone levels in man.

Diet, total plasma homocysteine concentrations and mortality rates in broiler chickens

2003 ◽  
Vol 83 (3) ◽  
pp. 601-604 ◽  
Author(s):  
S. E. Samuels
Keyword(s):  
Cardiovascular Disease ◽  
Sudden Death ◽  
Broiler Chickens ◽  
Independent Risk Factor ◽  
Total Mortality ◽  
Mortality Rates ◽  
Plasma Homocysteine ◽  
Sudden Death Syndrome ◽  
Total Plasma ◽  
Elevated Plasma

The aim of this study was to determine if total plasma homocysteine (HCY) concentrations and mortality rates due to ascites syndrome and (AS) sudden death syndrome (SDS) in broiler chickens could be lowered by diet. Elevated plasma HCY is an independent risk factor for cardiovascular disease in humans. A total of 828 day-old male broiler chickens (Arbor Acre) were fed, for 6 wk, either a basal practical diet or one supplemented with excess vitamins B6 and B12, folic acid and betaine to stimulate the degradation of HCY. The supplemented diet decreased plasma HCY by 17% (P < 0.05; n = 16 per diet). Total mortality due to AS and SDS was 18% lower in the supplemented diet but this difference was not statistically significant. Key words: Homocysteine, folate, chickens, cardiovascular disease, ascites, sudden death syndrome

scholarly journals Combination Treatment with T4 and T3: Toward Personalized Replacement Therapy in Hypothyroidism?

2012 ◽  
Vol 97 (7) ◽  
pp. 2256-2271 ◽  
Author(s):  
Bernadette Biondi ◽  
Leonard Wartofsky
Keyword(s):  
Quality Of Life ◽  
Thyroid Hormone ◽  
Replacement Therapy ◽  
Hormone Replacement ◽  
Hormone Action ◽  
Thyroid Hormone Replacement ◽  
Thyroid Hormone Action ◽  
Thyroid Hormone Replacement Therapy ◽  
Hypothyroid Patients

Abstract Context: Levothyroxine therapy is the traditional lifelong replacement therapy for hypothyroid patients. Over the last several years, new evidence has led clinicians to evaluate the option of combined T3 and T4 treatment to improve the quality of life, cognition, and peripheral parameters of thyroid hormone action in hypothyroidism. The aim of this review is to assess the physiological basis and the results of current studies on this topic. Evidence Acquisition: We searched Medline for reports published with the following search terms: hypothyroidism, levothyroxine, triiodothyronine, thyroid, guidelines, treatment, deiodinases, clinical symptoms, quality of life, cognition, mood, depression, body weight, heart rate, cholesterol, bone markers, SHBG, and patient preference for combined therapy. The search was restricted to reports published in English since 1970, but some reports published before 1970 were also incorporated. We supplemented the search with records from personal files and references of relevant articles and textbooks. Parameters analyzed included the rationale for combination treatment, the type of patients to be selected, the optimal T4/T3 ratio, and the potential benefits of this therapy on symptoms of hypothyroidism, quality of life, mood, cognition, and peripheral parameters of thyroid hormone action. Evidence Synthesis: The outcome of our analysis suggests that it may be time to consider a personalized regimen of thyroid hormone replacement therapy in hypothyroid patients. Conclusions: Further prospective randomized controlled studies are needed to clarify this important issue. Innovative formulations of the thyroid hormones will be required to mimic a more perfect thyroid hormone replacement therapy than is currently available.

Prospective Study of the Impact of Thyroid Hormone Replacement on Nasal Functions in Hypothyroid Patients

2013 ◽  
Vol 149 (2_suppl) ◽  
pp. P134-P134
Author(s):  
Elnur Akbarov ◽  
Hakan Birkent ◽  
Ozgur Karacalioglu ◽  
Omer Karakoc ◽  
Murat T. Akcam ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Prospective Study ◽  
Hormone Replacement ◽  
Thyroid Hormone Replacement ◽  
The Impact ◽  
Hypothyroid Patients

Effect of vitamin D3 loading and thyroid hormone replacement therapy on the decreased serum 25-hydroxyvitamin D level in patients with hypothyroidism

1986 ◽  
Vol 113 (3) ◽  
pp. 329-334 ◽  
Author(s):  
Julia Bársony ◽  
P. Lakatos ◽  
J. Földes ◽  
T. Fehér
Keyword(s):  
Vitamin D ◽  
Thyroid Hormone ◽  
Hormone Replacement ◽  
Substitution Therapy ◽  
Thyroid Hormone Replacement ◽  
Hormone Synthesis ◽  
Hydroxyvitamin D ◽  
Thyroid Hormone Replacement Therapy ◽  
25 Hydroxyvitamin D ◽  
Hypothyroid Patients

Abstract. Twelve hypothyroid subjects, 13 healthy and 12 healthy women with a slight deficiency of vitamin D were studied to distinguish seasonal changes from the thyroxine-dependent ones. Serum 25-hydroxyvitamin D levels of hypothyroid patients were lower than those of healthy individuals when the sera were obtained in the autumn. In hypothyroid patients a single oral dose of 100 000 IU vitamin D3 resulted in a smaller increase in 25-hydroxyvitamin D concentration than in controls having subclinical exogenous vitamin D deficiency. Substitution therapy with thyroid hormone, started in our study always in autumn, increased the 25-hydroxyvitamin D concentration in hypothyroid patients, which was opposite to the autumn-to-spring variation of this hormone observed in healthy controls. The increase of 25-hydroxyvitamin D, dehydroepiandrosterone and its sulphate values following substitution therapy in the hypothyroid patients may indicate that thyroid hormone(s) is (are) involved in the regulation of steroid hormone synthesis.

scholarly journals Evaluation of Thyroid Hormone Replacement Dosing in Morbidly Obese Hypothyroid Patients after Bariatric Surgery-Induced Weight Loss

2021 ◽  
Vol 10 (16) ◽  
pp. 3685
Author(s):  
Paula Juiz-Valiña ◽  
María Cordido ◽  
Elena Outeiriño-Blanco ◽  
Sonia Pértega ◽  
Paula Urones ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Weight Loss ◽  
Body Weight ◽  
Thyroid Hormone ◽  
Hormone Replacement ◽  
Ideal Body Weight ◽  
Morbidly Obese ◽  
Thyroid Hormone Replacement ◽  
Ideal Body ◽  
Hypothyroid Patients

The most frequent endocrine disease in obese patients is hypothyroidism. To date, there are no clear data regarding what happens to the dose of levothyroxine (LT4) after bariatric surgery (BS). The objective of the present study was to evaluate thyroid hormone replacement dose in morbidly obese hypothyroid patients after BS-induced weight loss. We explore the best type of measured or estimated body weight for LT4 dosing. We performed an observational study evaluating patients with morbid obesity and hypothyroidism who underwent BS. We included 48 patients (three men). In morbidly obese hypothyroid patients 12 months after BS-induced weight loss, the total LT4 dose or the LT4 dose/kg ideal body weight did not change, while there was a significant increase in LT4 dose/body surface area, LT4 dose/kg weight, LT4 dose/kg adjusted body weight, LT4 dose/kg body fat, and LT4 dose/kg lean body weight. There were no differences in LT4 dose and its variation between sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). The present study strongly suggests that LT4 dosing in obese hypothyroid patients can be individually adapted more precisely if it is based on ideal body weight.

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