Thyroid Hormone Secretion Research Articles

Antipyretic effect of inhaled Tetrastigma hemsleyanum polysaccharide on substance and energy metabolism in yeast-induced pyrexia mice via TLR4/NF-κb signaling pathway

Ethnopharmacological relevanceTetrastigma hemsleyanum Diels et Gilg, is one of the perennial evergreen plants with grass vine, which has obvious curative effect on severe infectious diseases. Although Tetrastigma hemleyanum has long been recognized for its capacity of antipyretic and antitoxic, its specific mechanism is unknown. Aim of the studyTo evaluate the antipyretic effect of Tetrastigma hemleyanum polysaccharide (THP) on mice with dry yeast-induced fever, and to explore its specific antipyretic mechanism. MethodsIn this study, THP was administered by aerosol in febrile mice. The rectal temperatures of treated animals were monitored at different time points. Histopathological evaluation and various inflammatory indexes were used to assess inflammatory damage. The concentration variations of the central neurotransmitter, endocrine system, substance and energy metabolism indicators were measured to explore the physiological mechanism. Quantitative real-time PCR, Western bolt and Immunohistochemistry were performed to identify the correlation between antipyretic and TLR4/NF-κB signaling pathway. ResultsTHP reduced the body temperature of febrile mice induced by dry yeast, as well as the levels of thermogenic cytokines and downregulated the contents of thermoregulatory mediators. THP alleviated the pathological damage of liver and hypothalamus caused by fever. In addition, THP decreased the secretion of thyroid hormone, substance and energy metabolism related indicators. Furthermore, THP significantly suppressed TLR4/NF-κB signaling pathway-related indicators. Conclusions: In conclusion, our results suggest that inhaled THP exerts antipyretic effect by mediating the thermoregulatory mediator, decreasing the content of pyrogenic factors to lower the body temperature, and eventually restoring the high metabolic level in the body to normal via inhibiting TLR4/NF-κB signaling pathway. The study provides a reasonable pharmacodynamic basis for the treatment of polysaccharide in febrile-related diseases.

Preoperative Preparation in Hyperthyroidism and Surgery in the Hyperthyroid State.

Hyperthyroidism is a clinical condition that develops due to the excessive production and secretion of thyroid hormones by the thyroid gland, leading to an elevated concentration of thyroid hormones in tissues. Hyperthyroidism is characterized by low TSH and elevated T3 and/or T4, with the most common causes being Graves' disease, toxic multinodular goiter, and solitary toxic adenoma. T3 is the peripherally active form of thyroid hormone, affecting nearly each tissue and system. The most prominent aspects of hyperthyroidism are related to the cardiovascular system. The treatment of hyperthyroidism includes three options: antithyroid drugs (ATDs), radioactive iodine therapy (RAI), and surgery. Among these treatment modalities, surgery is considered as the most effective one. For patients who are candidates for surgery, preoperative preparation is required to ensure that the thyroidectomy can be performed under optimal conditions. Preoperative preparation should be a combination therapy aimed at preventing the synthesis, secretion, and peripheral effects of thyroid hormones from the thyroid gland. Medications that can be used in this treatment include thionamides, beta-blockers, iodine, corticosteroids, cholestyramine, perchlorate, lithium, and therapeutic plasma exchange. These treatment options can be combined based on the patient's condition. While it is recommended that patients be made euthyroid through preoperative antithyroid treatment to prevent the feared complication, which is the thyroid storm, the supporting evidence is limited. Preoperative treatment does not prevent against thyroid storm whether the patient is euthyroid or hyperthyroid during surgery. Whether surgery should be delayed until biochemical euthyroidism is achieved in hyperthyroid patients remains a topic of debate. Recent studies suggest that thyroidectomy can be safely performed during the hyperthyroid phase by experienced anesthesiologists and surgeons without precipitating thyroid storm or increasing intraoperative and postoperative complications. Although achieving the euthyroid state before surgery is ideal in hyperthyroid patients, it is not always possible. Factors such as allergies to medications, drug side effects, treatment-resistant disease, patient noncompliance, and the urgency of definitive treatment are critical in determining whether hyperthyroidism can be controlled preoperatively. When surgery is necessary in hyperthyroid patients without achieving euthyroidism, the patient's overall condition and comorbidities should be evaluated together by the anesthesiologist, surgeon and endocrinologist, with particular attention to stabilizing the cardiovascular system. We believe that in hyperthyroid patients who are cardiovascularly stable during the hyperthyroid phase, thyroid surgery may not need to be delayed and can be performed safely.

An observational study to determine relationship of serum hydrogen sulphide level in hypothyroid patients in a medical college in Kolkata

Hypothyroidism is an endocrinopathy eventuate due to destruction of thyroid cells incapacitating synthesis of thyroid hormones. HS which is a gas signaling molecule that might protect synthesis and secretion of thyroid hormone by upregulating the expression levels of thyroid hormone synthesis-related proteins and promotingting Thyroid peroxidase (TPO) activity through S-sulphydration of sirtuin-1 (SIRT-1). Depending on this fact we measured the HS level in a group of hypothyroid patient. The plasma H S level in case in our study was 33.95 ± 4.14 micromol/l with the range from 27.82 to 43.94 micromol/l. This was significantly (P< 0.001) lower than age/sex matched healthy controls which was 64.67±4.25 micromol/l, with a range from 49.81 to 80.02 micromol/l. this study also elucidated that plasma HS levels were significantly correlated with level of diagnostic parameters of hypothyroidism.

Effects of cooling on thyroid hormone secretion and growth of eastern bluebird (Sialia sialis) nestlings

Achieving endothermic homeothermy is a critical aspect of avian development. In pre-homeothermic altricial nestlings, variation in parental brooding behavior results in variable exposure of nestlings to cooling, with consequences for the developing endocrine system. Nestlings facing repeated cooling challenges may benefit from upregulation of thyroid hormone secretion, allowing for earlier onset of thermoregulatory capability to mitigate the potentially negative effects of exposure to non-optimal temperatures during development. We examined the effects of (1) a single cooling challenge on thyroid hormone secretion in pre-homeothermic nestlings, and (2) repeated cooling challenges prior to the onset of homeothermy on nestling growth and thyroid hormone secretion prior to fledging. We found that pre-homeothermic eastern bluebird nestlings exposed to a single cooling challenge increased circulating triiodothyronine (T3), demonstrating that the thyroid system can be activated by cooling early in life. However, we found no consequences of repeated cooling during the first week of life on nestling growth or baseline T3 levels prior to fledging. This work addresses how the nestling hypothalamic-pituitary-thyroid axis responds to acute cooling challenges prior to the development of endothermic homeothermy; future work will confirm whether such responses allow nestlings to hasten the onset of physiological thermoregulation when conditions demand it.

Receptor modulators associated with the hypothalamus -pituitary-thyroid axis.

The hypothalamus-pituitary-thyroid (HPT) axis maintains normal metabolic balance and homeostasis in the human body through positive and negative feedback regulation. Its main regulatory mode is the secretion of thyrotropin (TSH), thyroid hormones (TH), and thyrotropin-releasing hormone (TRH). By binding to their corresponding receptors, they are involved in the development and progression of several systemic diseases, including digestive, cardiovascular, and central nervous system diseases. The HPT axis-related receptors include thyrotropin receptor (TSHR), thyroid hormone receptor (TR), and thyrotropin-releasing hormone receptor (TRHR). Recently, research on regulators has become popular in the field of biology. Several HPT axis-related receptor modulators have been used for clinical treatment. This study reviews the developments and recent findings on HPT axis-related receptor modulators. This will provide a theoretical basis for the development and utilisation of new modulators of the HPT axis receptors.

Production cooked sausages with the addition of iodized salt

Iodine deficiency in the biosphere, mainly in the soil, leads to endemic goiter and other iodine deficiency disorders. As shown by numerous studies, this disease affects over 1 billion people in the world. Endemic goiter and much of the territory of Ukraine, including the Vinnytsia region. Presented current research study of recipes and technologies on system-cooked sausages. Currently, boiled sausage enjoys relatively high demand among the population because it is significant for most people, giving it an advantage. Innovation activity represents one of the most effective directions. It should facilitate the development of innovative activity that promotes penetration into new markets and production growth. Today, the most essential and effective innovative organizational and technical measures introduced in sausage production can be considered are the use of new recipes for manufacturing products and the installation of new equipment, which can significantly reduce the cost of manual labor and power inputs and improve product quality and reduce the share of marriage. Sausage production is seen as a thermochemical method of preserving meat products. For each type of sausage, set production process-approved technological instructions and recipes. Strict adherence to recipes, specialized instructions, and sanitary regimes is a prerequisite for obtaining high-quality links. Crucial in the production of sausages is raw. The primary raw materials are beef and pork. Occasionally, use lamb and horsemeat. Equally important is the creation of a new generation of products that have general strengthening and preventive action. The components of these products can protect the body from the harmful effects of the environment and the emergence of human diseased cells. The constant lack of iodine leads to a reduction in the synthesis and secretion of the primary thyroid hormone - thyroxine. The role of thyroid hormones in the body is extremely high, and most of the vital functions are performed by their participation. The main physiological effects of thyroid hormone are stimulating synthesis, growth, development, and differentiation of tissues. Developed products to include microorganisms that can synthesize biologically active structures (antibodies, receptors, hormones) that contribute to the removal or destruction of harmful decay and systems, thereby preventing human disease.

The relation between oral health and body mass index among women with hyperthyroidism

Background: Hyperthyroidism is a medical condition in which excessive synthesis and secretion of thyroid hormones into the blood. According to multiple research, hyperthyroidism is linked to weight loss and increased metabolism.
 Objective: To assess how hyperthyroidism affects oral health in relation to body mass index.
 Patients and Methods: The sample was composed of 90 female patients aged 25-45 years include hyperthyroid group and healthy group, the hyperthyroid patients were diagnosed by specialist and under treatment with carbimazole.Clinical evaluation of caries was done according to World Health Organization(2013). The body mass index was measured from the patient’s weight and height, according to the formula World Health Organization(2000). Plaque Index of Silness and Löe was used to evaluate dental plaque (1964),Using the gingival index of Loe and Silness the gingival inflammation was evaluated (1963).
 Results: Found the Body mass index in the hyperthyroid group was higher than the healthy group with significant difference. The most correlations between caries and body mass index in the hyperthyroid group were weak negative not significant while in the healthy group most correlations were weak positive not significant, the correlations of Gingival index and body mass index were weak positive not significant in both groups.The plaque index had weak negative in hyperthyroid while in control positive correlation and all correlation were not significant.
 Conclusion: In the present study,the Body mass index higher among women with hyperthyroidism under treatment with carbimazole and the correlation between caries experience and body mass index was negative and not significant.

Perioperative hormone level changes and their clinical implications in patients with pituitary adenoma: a retrospective study of 428 cases at a single center.

This study employs case data analysis to elucidate alterations in hormone levels pre and post-surgery among patients with pituitary adenoma. Moreover, it investigates the influence of various associated factors on endocrine function. A retrospective analysis was conducted on clinical data from 428 patients who underwent surgical treatment within a short period at a single center. Statistical methods were employed to examine detailed hormone level fluctuations before and after surgery in patients with pituitary adenoma, along with their interrelations with different factors. Between January 2016 and October 2022, a total of 428 consecutive patients with pituitary adenoma underwent surgical treatment. Of these, 232 were males and 196 were females, with an average age of 45.91 years (range: 16-84, standard deviation: 12.18). Univariate analysis indicated that females exhibited a higher susceptibility to preoperative endocrine dysfunction (p < 0.05). Conversely, males, patients with larger tumor volumes, and older patients were more prone to preoperative pituitary insufficiency. Postoperatively, the most substantial remission rate occurred in prolactin (77.4%), followed by growth hormone (GH) (71.8%) and cortisol (4/6). The highest recovery rate in functions was observed in growth hormone secretion function (80%), followed by pituitary-adrenal axis hormone secretion function (56.3%) and pituitary-thyroid axis hormone secretion function (47.5%). The most noteworthy incidence of newly developed postoperative endocrine deficiencies was found in the pituitary-adrenal axis (31.8%), while the occurrence rates of deficiencies in other axes were relatively low. The elevated postoperative remission rate of growth hormone correlated with a higher surgical resection rate and lower preoperative growth hormone levels. Additionally, lower preoperative prolactin levels corresponded to a higher remission rate of prolactin postoperatively. Furthermore, the restoration of postoperative thyroid hormone secretion function was associated with higher preoperative free thyroxine levels. Reduced postoperative cortisol secretion function was linked to multiple surgeries and an extended interval between hormone retesting and surgery. Surgical intervention effectively ameliorates endocrine disorders in pituitary adenoma patients, thereby mitigating symptoms and enhancing their quality of life. Preoperative management of growth hormone and prolactin levels facilitates an increased remission rate of these hormones post pituitary adenoma surgery. Patients displaying preoperative thyroid hormone secretion dysfunction should be considered for active supplementation therapy. Whenever feasible, complete tumor resection is recommended. For patients undergoing reoperation or multiple surgeries, vigilant postoperative cortisol monitoring and supplementation should be thoughtfully administered.

Sustained Pituitary T3 Production Explains the T4-mediated TSH Feedback Mechanism.

The regulation of thyroid activity and thyroid hormone (TH) secretion is based on feedback mechanisms that involve the anterior pituitary TSH and medial basal hypothalamus TSH-releasing hormone. Plasma T3 levels can be "sensed" directly by the anterior pituitary and medial basal hypothalamus; plasma T4 levels require local conversion of T4 to T3, which is mediated by the type 2 deiodinase (D2). To study D2-mediated T4 to T3 conversion and T3 production in the anterior pituitary gland, we used mouse pituitary explants incubated with 125I-T4 for 48 hours to measure T3 production at different concentrations of free T4. The results were compared with cultures of D1- or D2-expressing cells, as well as freshly isolated mouse tissue. These studies revealed a unique regulation of the D2 pathway in the anterior pituitary gland, distinct from that observed in nonpituitary tissues. In the anterior pituitary, increasing T4 levels reduced D2 activity slightly but caused a direct increase in T3 production. However, the same changes in T4 levels decreased T3 production in human HSkM cells and murine C2C12 cells (both skeletal muscle) and mouse bone marrow tissue, which reached zero at 50 pM free T4. In contrast, the increase in T4 levels caused the pig kidney LLC-PK1 cells and kidney fragments to proportionally increase T3 production. These findings have important implications for both physiology and clinical practice because they clarify the mechanism by which fluctuations in plasma T4 levels are transduced in the anterior pituitary gland to mediate the TSH feedback mechanism.

The Relationship between Thyrotropin Serum Concentrations and Thyroid Carcinoma.

Thyroid Stimulating Hormone (TSH) is a hormone secreted by the pituitary gland and plays a role in regulating the production and secretion of thyroid hormones by the thyroid gland. This precise feedback loop is essential for maintaining a harmonious balance of thyroid hormones in the body, which are vital for numerous physiological processes. Consequently, TSH serves as a significant marker in assessing thyroid function, and deviations from normal TSH levels may indicate the presence of a thyroid disorder. Thyroid cancer (TC) is the malignant tumor within the endocrine system. In recent years, numerous experts have dedicated their efforts to discovering efficacious biomarkers for TC. These biomarkers aim to improve the accurate identification of tumors with a poor prognosis, as well as facilitate active monitoring of tumors with a more favorable prognosis. The role of TSH in the thyroid gland underscores its potential influence on the occurrence and progression of TC, which has garnered attention in the scientific community. However, due to the limited scope of clinical research and the dearth of high-quality foundational studies, the precise impact of TSH on TC remains unclear. Consequently, we present a comprehensive review of this subject, aiming to offer a valuable reference for future research endeavors.

Morphofunctional state of the thyroid gland in rats with prolonged low-dose exposure to deltamethrin

The thyroid gland is very sensitive to various stress factors, including chemical ones. Meanwhile, the effect that many ecotoxicants have on the animal endocrine system has not been studied. The effect of cyanide-containing synthetic pyrethroids on the synthesis and secretion of thyroid hormones during prolonged low-dose exposure remains an open question. This research was aimed at assessing the morphofunctional state of the thyroid gland in laboratory rats under the specified exposure regime. The studies were conducted on 48 male Wistar rats. When modeling the effect of low doses of deltamethrin on animals, the substance was administered to rats at a dose of 1/100 LD50, and the experiment lasted for 120 days. The concentrations of thyroid-stimulating hormone, total thyroxine (T4), triiodothyronine (T3), and the ratio T4/T3 were determined in the rats' blood. The solid-phase enzyme immunoassay method was used to determine hormones. For histological examination, the thyroid gland of animals was fixed in a 4% neutral formaldehyde solution. Sections of paraffin blocks were stained with hematoxylin and eosin. Prolonged low-dose exposure to deltamethrin caused hypofunction of the thyroid gland in laboratory rats, which was accompanied by a decrease in the level of thyroid hormones in the blood serum. The stimulating effect of the pituitary gland increased compensatorily due to the additional release of thyroid-stimulating hormone. At the same time, there was a change in the ratio of T4/T3 in the blood. The histological patterns of the thyroid gland were characterized by a decrease in the thyrocyte area, growth of follicles, and colloid densification.

Thyroid Function in Children with Cyanotic and Non-Cyanotic Congenital Heart Disease.

Congenital heart disease (CHD) is one of the common diseases of childhood, which is classified into non-cyanotic and cyanotic types. It can affect thyroid function and lead to disruptions in thyroid hormone secretion and hypofunction. This study aimed to evaluate thyroid function in patients younger than 2 years old with cyanotic and non-cyanotic CHD. In our study, 101 patients (female/male: 50/51) were included. The thyroid-stimulating hormone and thyroid hormones such as thyroxine (T4) and triiodothyronine (T3) were measured using the electrochemiluminescence method, and thyroid peroxidase antibodies were measured by an enzyme-linked immunosorbent assay. Subclinical hypothyroidism referred to normal levels of T4, with elevated levels of thyroid-stimulating hormone in the serum. The frequency of subclinical hypothyroidism and hypothyroidism in patients with cyanotic CHD was estimated at 27.5% and 10%, respectively, and 1 patient had hyperthyroidism. The majority of cyanotic and non-cyanotic CHD cases were diagnosed with tetralogy of Fallot (30%) and patent ductus arteriosus (32.79%). There were no significant differences between cyanotic and non-cyanotic groups regarding T3, T4, free T3, free T4, and anti-thyroid peroxidase antibody levels (0.389, 0.142, 0.354, 0.248, and 0.333, respectively). Based on the present findings, subclinical hypothyroidism is a common finding in cyanotic CHD patients during childhood, which is associated with increased levels of oxygen saturation, severity of cyanosis, and age.

Gallstone Disease and Its Correlation With Thyroid Disorders: A Narrative Review.

Over the years, several studies have revealed an important link between thyroid disorders and gallstone disease. According to these studies, hypothyroidism and hyperthyroidism are associated with cholesterol gallstone disease. This association between thyroid hormone disorders and cholesterol gallstone disease is due to the importance of thyroid hormones on cholesterol synthesis, bile functioning and content, and gallbladder motility. Several genes and receptors have been found on the thyroid gland, liver, and gallbladder to verify this association. These genes affect thyroid hormone secretion, lipid metabolism, and bile secretion. Defects in these various gene expression and protein functions lead to bile duct diseases. Other causes that lead to cholesterol gallstone disease are supersaturation of the bile with cholesterol and impaired gallbladder motility, which leads to bile stasis. This article has discussed these factors in detail while highlighting the association between thyroid hormones and cholesterol gallstone disease.

REVIEW OF SARS-CORONAVIRUS-2 REPERCUSSIONS ON THYROID GLAND IN THE CONTEXT OF HYPERTHYROIDISM

The thyroid gland may generate, store, and release hormones (such as Triiodothyronine and Thyroxin also called T3 and T4 hormones respectively) into the bloodstream and let them go to the body's cells. Every enzymatic process in the production and secretion of thyroid hormones is controlled by Thyroid stimulating hormone (TSH). All people worldwide are susceptible to thyroid disease, which is often accompanied by hyperthyroidism and hypothyroidism. The thyroid's structural proximity to the upper airways, a main route for coronavirus entry, holds up the idea that the thyroid gland might be a target for Covid-19 or SARS-CoronaVirus-2. When the thyroid gland makes and secretes too much thyroid hormone, it is referred to as hyperthyroidism and if the patients do not take any precautions, hyperthyroidism may lead to cardiac hypertrophy. The Covid-19 epidemic had a substantial influence on our daily lives and has unexpectedly changed the way of medical research. This review aimed to discuss the effects of SARS-CoronaVirus-2 on the Thyroid Gland in the Context of Hyperthyroidism and related causing diseases, highlighting the common causing diseases of hyperthyroidism along with their treatments. We also highlight the impact of SARS-CoronaVirus-2 and its mRNA immunization. So that future studies should focus on the number of important advances and improved drug management in the treatment of Thyroid relating diseases, which may or may not be triggered by the coronavirus and its immunization.

Interactions between Polygenetic Variants and Lifestyle Factors in Hypothyroidism: A Hospital-Based Cohort Study.

Hypothyroidism is a prevalent endocrine disorder and is associated with a variety of metabolic disturbances. This study aimed to investigate the polygenic variants associated with hypothyroidism risk and the interaction of polygenic risk scores (PRS) with dietary patterns in influencing disease risk in 56,664 participants aged >40 in a hospital-based cohort. The participants were classified as having hypothyroidism (n = 870) diagnosed by a physician and no hypothyroidism (n = 55,794). Genetic variants associated with hypothyroidism were identified using a genome-wide association study (GWAS). Genetic variants interacting with each other were selected using a generalized multifactor dimensionality reduction analysis, and the PRS generated was evaluated for interaction with lifestyle parameters. Coffee, alcohol, meat intake, and a Korean balanced diet were inversely associated with hypothyroidism risk, as were selenium, copper, and manganese intakes. White blood cell (WBC) counts and serum alkaline phosphatase and triglyceride concentrations were positively associated with hypothyroidism risk, as were osteoporosis and thyroid cancer. The GMDR analysis generated a three-single nucleotide polymorphism (SNP) model comprising dual oxidase-1 (DUOX1)_rs1648314; thyroid-stimulating hormone receptor (TSHR)_rs75664963; and major histocompatibility complex, class-II, DQ Alpha-1 (HLA-DQA1)_rs17426593. The PRS derived from the three- and seven-SNP models were associated with a 2.11- and 2.32-fold increase in hypothyroidism risk, respectively. Furthermore, the PRS from the three-SNP model showed interactions with WBC counts, wherein the positive association with hypothyroidism risk was more pronounced in participants with low WBC counts than those with high WBC counts (≥4 × 109 /L). Dietary patterns, such as the plant-based diet (PBD) and the Western-style diet (WSD), along with smoking status, exhibited interactions with the PRS, influencing hypothyroidism risk. In participants with a high PRS, those in the high-PBD, low-WSD, and smoker groups had a higher proportion of hypothyroidism than those in the low-PBD, high-WSD, and non-smoker groups. In conclusion, genetic variants related to immunity and thyroid hormone secretion were linked to hypothyroidism risk, and their PRS interacted with PBD and WSD intake and smoking status. These results contribute to a better understanding of hypothyroidism and its prevention strategies for precision medicine intervention.

Pharmacodynamic and pharmacokinetic properties of the combined preparation of levothyroxine plus sustained- release liothyronine; a randomized controlled clinical trial

BackgroundUnderstanding pharmacokinetics (PK) and pharmacodynamics (PD) of the sustained-release liothyronine (SR-T3) is of paramount importance to design therapeutic regimens that are able to simulate normal thyroid hormone secretion while avoiding excursions in the T3 serum concentration. Here, we designed a parallel randomized clinical trial to characterize the PK and PD of the combined preparations of LT4 + SR-T3 in hypothyroid patients.MethodsRadioiodine-treated hypothyroid patients over 20 years of age, who attained euthyroidism with LT4 monotherapy were recruited from the Endocrine Clinic in Tehran. The patients were allocated to two intervention groups of group A: 9 µg SR-T3 plus 68.5 μg LT4 (ratio 1:7.5) and group B: 12 µg SR-T3 plus 60 µg LT4 (ratio 1:5), and a control group with LT4 monotherapy. For PD study, thyroid hormone profile was evaluated at 8 and 12 weeks intervals after intervention. To assess PK properties of SR-T3, T3-Cmax, T3-Tmax and AUC0 − 24 were calculated at the last visit.ResultsSerum T4 and FT4 concentrations decreased in the intervention groups after 3 months. No significant difference was observed in serum T3 and FT3 concentrations before and after intervention. Serum T3/T4 ratio increased significantly in the intervention groups after intervention, with the highest increase in group B from 8.6 ± 2.03 at baseline to 12.2 ± 1.6. Comparison of trial groups at follow-up showed no differences in serum TSH, T4, T3 and T3/T4 concentrations among different groups. During 24 h, minimal variation in serum T3 concentration was observed in group B with mean ∆T3 of 15.4 ± 10.5 ng/dl. T3-Tmax, T3-Cmax and AUC0 − 24 in the combined sustained-release preparation were 4.38 ± 1.1 h., 101.0 ± 5.7 ng/dl and 2257 ± 110 ng.h/L, respectively which were significantly different from the control group.ConclusionCombined treatment with a single dose of SR-T3 plus LT4 is associated with increased serum T3/T4 ratio and minimal excursions in serum T3 concentration during 24 h; however, it was not significantly different from the control group. To incorporate sustained-release T3 in the management of hypothyroidism, a higher ratio of SR-T3 to LT4 than that of the previously recommended by the international organizations is suggested.IRCT registration numberIRCT20100922004794N13. https://www.irct.ir/search/result?query=IRCT20100922004794N13. Registration date: 08/12/2021.

Diagnosis and management of thyroid disorders and thyroid hormone supplementation in adult horses and foals.

Equine thyroid disorders pose a diagnostic challenge in clinical practice because of the effects of nonthyroidal factors on the hypothalamic-pituitary-thyroid axis, and the horse's ability to tolerate wide fluctuations in thyroid hormone concentrations and survive without a thyroid gland. While benign thyroid tumours are common in older horses, other disorders like primary hypothyroidism or hyperthyroidism in adult horses and congenital hypothyroidism in foals are rare. There is a common misunderstanding regarding hypothyroidism in adult horses, especially when associated with the clinical profile of obesity, lethargy, and poor performance observed in dogs and humans. Low blood thyroid hormone concentrations are often detected in horses as a secondary response to metabolic and disease states, including with the nonthyroidal illness syndrome; however, it is important to note that low thyroid hormone concentrations in these cases do not necessarily indicate hypothyroidism. Assessing equine thyroid function involves measuring thyroid hormone concentrations, including total and free fractions of thyroxine (T4) and triiodothyronine (T3); however, interpreting these results can be challenging due to the pulsatile secretion of thyroid hormones and the many factors that can affect their concentrations. Dynamic testing, such as the thyrotropin-releasing hormone stimulation test, can help assess the thyroid gland response to stimulation. Although true hypothyroidism is extremely rare, thyroid hormone supplementation is commonly used in equine practice to help manage obesity and poor performance. This review focuses on thyroid gland pathophysiology in adult horses and foals, interpretation of blood thyroid hormone concentrations, and evaluation of horses with thyroid disorders. It also discusses the use of T4 supplementation in equine practice.

Potential role of latent toxoplasmosis in inducing thyroid disorders with relevance to autoimmune thyroid disease and interleukin-33 level during pregnancy

Background and Aim: Latent toxoplasmosis is the most frequently occurring parasitic infection worldwide, which causes hormonal and behavioral changes that seriously affect pregnant women. It has also been linked to several autoimmune diseases, including autoimmune thyroid disease (AITD). This study aimed to investigate the association between Toxoplasma gondii seropositivity and thyroid dysfunction, considering the impact of latent toxoplasmosis on the prevalence of maternal AITD and interleukin-33 (IL-33) levels in infected and non-infected pregnant women. Materials and Methods: We conducted a cross-sectional study on 400 pregnant women aged 15–50 in the 8th–36th gestational week. Toxoplasma status was confirmed by detecting anti-Toxoplasma immunoglobulin (Ig)G antibodies. Recent and past chronic toxoplasmosis status was differentiated using the Toxoplasma IgG avidity test. Free triiodothyronine (FT3), free thyroxine, and thyroid-stimulating hormone (TSH) levels were determined to evaluate thyroid disorders. Antibodies against thyroid peroxidase, thyroglobulin, and TSH receptor were assessed to distinguish patients with autoimmune thyroid disorders from those with other thyroid diseases. We divided the subjects into four groups (Toxo+ and abnormal hormone level, Toxo– and normal hormone level, Toxo+ and normal hormone level, and Toxo– and abnormal hormone level) and evaluated their IL-33 levels to investigate its role during the infection. All the tests were performed using the enzyme-linked immunosorbent assay. Results: The results showed that (205/400, 51.2%) samples were seropositive for anti-Toxoplasma IgG antibodies. Of these, (25/205, 12.2%) and (180/195, 87.8%) had recent and past chronic infections, respectively. High infection rates were reported among rural dwellers (150/400, 37.5%) and those in their 3rd trimester (110/400, 27.5%). Of the 205 seropositive patients, (131/205, 63.9%) had thyroid disorders, among which (69/205, 33.7%) and (119/205, 58.0%) had abnormal FT3 and TSH hormone levels, respectively. In contrast, out of 195 Toxoplasma seronegative samples, (99/195, 50.8%) had thyroid disorders; (48/195, 24.6%) and (90/195, 46.2%) had abnormal FT3 and TSH hormone levels, respectively. Groups with abnormal FT3 and TSH levels had significantly higher seropositive anti-toxoplasma IgG antibodies (p = 0.01). Women with seropositive anti-Toxoplasma IgG antibodies had a high hypothyroidism rate (115/205, 56.1%) compared with those with seronegative anti-Toxoplasma IgG antibodies (86/195, 44.1%). We found an association between toxoplasmosis and thyroid status (p &lt; 0.05). Out of 400 samples, 85 (85/400, 21.25%) had AITD. Further, (58/205, 28.3%) of women with seropositive anti-toxoplasma IgG antibodies had AITD compared to (27/195, 13.85%) in the seronegative ones. We found a significant association between toxoplasmosis and AITD (p &lt; 0.05). The IL-33 level was highest in the Toxo+ and abnormal hormone level group (210.86 ± 44.39 pg/mL) and lowest in the Toxo-and normal hormone level group (22.27 ± 8.41 pg/mL). Conclusion: Our results suggest that latent toxoplasmosis was significantly associated with thyroid hormone secretion, which might stimulate the immune system, leading to the development of AITD among pregnant women. Furthermore, the T. gondii seroprevalence was positively correlated with pregnant patients who were rural dwellers and in their 3rd trimester. Keywords: autoimmune thyroiditis disease, interleukin-33, pregnancy, thyroid hormones, toxoplasmosis.

Subclinical Hypothyroidism among Patients with COVID-19 Infection in a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Hypothyroidism occurs as a consequence of chronic autoimmune inflammation of the thyroid gland, which occurs due to the reduced function in the secretion of thyroid hormones. The coronavirus disease infection has shown many complications in all organic systems, during the acute phase of infection and in the post-COVID-19 period. SARS-CoV-2 may induce thyroid dysfunction that is usually reversible, including subclinical and atypical thyroiditis. The aim of this study was to find out the prevalence of subclinical hypothyroidism among patients with COVID-19 infection in a tertiary care centre. A descriptive cross-sectional study was conducted in the Department of Internal Medicine of a tertiary care centre from 1 September 2022 to 28 February 2023 after obtaining ethical approval from the Research and Institutional Review Committee (Reference number: 15-079/080). Convenience sampling method was used. Point estimate and 95% Confidence Interval were calculated. Among 38 patients with COVID-19, subclinical hypothyroidism was seen among 23 (60.53%) (44.99-76.07, 95% Confidence Interval). The prevalence of subclinical hypothyroidism among COVID-19 patients was found to be similar to other studies done in similar settings. COVID-19; hypothyroidism; thyroid gland.

Acquired Hypothyroidism in Children.

Acquired hypothyroidism is generally also referred to as juvenile hypothyroidism. Hypothyroidism is due to the deficient secretion of thyroid hormones causing metabolic and neurological sequelae at the cellular level. It can present as overt hypothyroidism wherein the thyroid hormones (T4 and T3) secretion fall and thyrotropin (TSH) rises. Acquired hypothyroidism frequently presents between 9 and 11 y of age and is rarely seen before 4 y of age. Approximately 80% of the children and adolescents are asymptomatic at the time of diagnosis. Children with moderate to severe hypothyroidism often present for evaluation of poor growth, constipation, lethargy and/or dry skin. A detailed history and examination will provide us with enough clues for diagnosing hypothyroidism. Primary hypothyroidism can be diagnosed with raised TSH with subnormal levels of T3 and T4. Titres of thyroid antibodies - Anti-thyroperoxidase (TPO) and anti-thyroglobulin (ATG) antibodies, will be high in autoimmune hypothyroidism. Subclinical hypothyroidism is diagnosed with mildly elevated or high normal levels of TSH with free T4 being in the normal range. Insufficient secretion of thyrotropin from the pituitary causes central hypothyroidism. Acquired hypothyroidism is treated by replacement with levothyroxine. Regular monitoring of thyroid profile is necessary for adjusting doses of levothyroxine. Close monitoring and individualization of levothyroxine therapy is essential for normal growth and development of the child.