Thyroxine Concentrations Research Articles

Changes in thyroid function levels in female patients with first-episode bipolar disorder.

The identification of molecular biomarkers for bipolar disorder is anticipated to greatly improve the diagnosis and treatment of this disease. The objective of this case-control study is to determine whether the blood thyroid hormone levels in bipolar disorder patients are associated with different types of first onset. From August 1, 2020 to July 31, 2021 a total of 120 female patients diagnosed with bipolar disorder and hospitalized at Qingdao Mental Health Center were recruited as the case group, including 60 patients with depression as their first onset (depression first-episode group, DF) and 60 with mania/hypomania as their first onset (mania/hypomania first-episode group, M/HF). A group of 60 healthy adult females matching general demographic data, such as race and age, were selected as the control group. Blood samples were taken from both groups to measure serum triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) concentrations. The duration of current onset in the M/HF group was significantly less than that in the DF group (23.1 ± 20.2 vs. 125.2 ± 41.0 days). About 27% of patients in the M/HF group had thyroid abnormalities, in contrast to 60% in the DF group. The blood T3 and T4 levels in both the M/HF group and the DF group, as well as the TF3 levels in the DF group, were significantly lower as compared to control. The M/HF group had significantly higher T3 and FT3 levels than the DF group. The blood T3 levels were inversely correlated with the Young's Mania Scale score and the Hamilton Depression Scale score in both the M/HF and DF groups. Thyroid dysfunction resulting in reduced levels of blood thyroid levels may be involved in the disease progression of bipolar disorder, and correlated with the clinical symptoms in patients with depression or mania as the first episode.

Effects of genetic selection for fast growth on the development of wooden breast myopathy in broilers

ABSTRACT 1. This study investigated the physiological and molecular mechanisms leading to wooden breast (WB) by comparing growth parameters, oxygen consumption rate, thyroid hormone and gene expression patterns in fast- versus slow-growing broiler lines (Cobb500 and L1986, respectively). 2. WB was observed in Cobb500 broilers only and was first diagnosed on d 21 post-hatch. Compared to the slow-growing L1986, Cobb500 showed a significantly higher growth rate, relative breast weight, breast thickness, meat pH and water-retention capacity (drip loss). Correspondingly, there was significantly lower relative heart weight, relative right ventricular weight, triiodothyronine and thyroxine concentrations and oxygen consumption rate. 3. Compared to No-WB Cobb500, the WB-affected samples exhibited higher relative breast weight, breast thickness and drip loss and lower plasma total thyroxine (T4) concentrations. 4. Selection for fast growth was associated with differential expression of genes involved in hypoxia (PLOD2), energy metabolism (FABP3, FABP4, CD36, and LPL), endoplasmic reticulum stress, muscle regeneration (CSRP3) and fibre-type switching (ANKRD1). WB-affected samples exhibited an upregulation of CSRP3, PLOD2 and ANKRD1, while CD36 was downregulated. Taken together, selection for fast growth and muscle gain is not matched by adequate cardiac and metabolic support systems.

The effect of metformin therapy on serum thyrotropin and free thyroxine concentrations in patients with type 2 diabetes: a meta-analysis

Type 2 diabetes and thyroid function disorders are two common chronic endocrine disorders with the high prevalence in various populations. Metformin is well established as the first-line drug therapy for managing diabetes mellitus. In this meta-analysis, we aimed to determine the effect of metformin on serum TSH and FT4 concentrations in patients with type 2 diabetes. We searched PubMed, Scopus, web of science, Cochrane library, and google scholar to collect information on the effect of metformin on serum TSH and FT4 levels. Demographic and clinical information and serum TSH and FT4 concentrations before and after metformin treatment were extracted. Studies on patients over 18 years of age were included. A total of 11 studies including 1147 patients were selected for the final analysis. In hypothyroid patients, the TSH level decreased significantly after treatment with metformin (Hedges’s g:1.55, 95%CI 0.93–2.16, p-value < 0.001); FT4 level increased slightly after taking metformin, but the increase was not significant (Heddges’s g: − 0.30, 95%CI − 0.90,0.31, p-value = 0.34). In euthyroid subjects, the slight decrease found in TSH and FT4 concentrations was not statistically significant. Metformin reduces TSH levels in hypothyroid patients; however, it has no effect on TSH levels in euthyroid patients. Metformin does not affect serum FT4 levels in euthyroid and hypothyroid patients.

Stress-Mediated Abnormalities in Regional Myocardial Wall Motion in Young Women with a History of Psychological Trauma.

Psychosocial stress has been associated with the development and progression of atherosclerotic cardiovascular disease (CVD). Previously, we reported subtle differences in global longitudinal strain in somatically healthy women with a psychiatric diagnosis of borderline personality disorder (BPD). This study aimed to investigate the impact of BPD on segmental myocardial wall motion using speckle tracking echocardiography (STE) analysis. A total of 100 women aged between 18 and 38 years were included in this study. Fifty patients meeting the diagnostic criteria for BPD were recruited from the Department of Psychiatry (LWL-University Hospital Bochum) and compared with fifty age-matched healthy control subjects without previous cardiac disease. Laboratory tests and STE were performed with segmental wall motion analysis. The BPD group had a higher prevalence of risk factors for CVD, with smoking and obesity being predominant, when compared with the control group. Other cardiovascular parameters such as blood pressure, glucose, and cholesterol levels were also elevated, even though not to pathological values. Moreover, in the STE analysis, the BPD group consistently exhibited decreased deformation in nine myocardial wall regions compared with the control group, along with a shift toward higher values in the distribution of peak pathological segments. Additionally, significantly higher values of free thyroxine concentration and thyroid's secretory capacity were observed in the BPD group, despite falling within the (high-) normal range. BPD is associated with chronic stress, classical risk factors, and myocardial wall motion abnormalities. Further exploration is warranted to investigate the relationship between high-normal thyroid metabolism, these risk factors, and myocardial function in BPD patients. Long-term follow-up studies would be valuable in confirming the potential for predicting adverse events.

Hyperthyroidism: A Review.

Overt hyperthyroidism, defined as suppressed thyrotropin (previously thyroid-stimulating hormone) and high concentration of triiodothyronine (T3) and/or free thyroxine (FT4), affects approximately 0.2% to 1.4% of people worldwide. Subclinical hyperthyroidism, defined as low concentrations of thyrotropin and normal concentrations of T3 and FT4, affects approximately 0.7% to 1.4% of people worldwide. Untreated hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes. It may lead to unintentional weight loss and is associated with increased mortality. The most common cause of hyperthyroidism is Graves disease, with a global prevalence of 2% in women and 0.5% in men. Other causes of hyperthyroidism and thyrotoxicosis include toxic nodules and the thyrotoxic phase of thyroiditis. Common symptoms of thyrotoxicosis include anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance. Patients with Graves disease may have a diffusely enlarged thyroid gland, stare, or exophthalmos on examination. Patients with toxic nodules (ie, in which thyroid nodules develop autonomous function) may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes. Etiology can typically be established based on clinical presentation, thyroid function tests, and thyrotropin-receptor antibody status. Thyroid scintigraphy is recommended if thyroid nodules are present or the etiology is unclear. Thyrotoxicosis from thyroiditis may be observed if symptomatic or treated with supportive care. Treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease include antithyroid drugs, radioactive iodine ablation, and surgery. Treatment for subclinical hyperthyroidism is recommended for patients at highest risk of osteoporosis and cardiovascular disease, such as those older than 65 years or with persistent serum thyrotropin level less than 0.1 mIU/L. Hyperthyroidism affects 2.5% of adults worldwide and is associated with osteoporosis, heart disease, and increased mortality. First-line treatments are antithyroid drugs, thyroid surgery, and radioactive iodine treatment. Treatment choices should be individualized and patient centered.

Features of the natural course of subclinical hypothyroidism in young athletes

Objective: to assess the natural course of subclinical hypothyroidism in young athletes.Methods: In the prospective single-center uncontrolled study, data from 3,062 outpatient records of young athletes (members of the Russian national team) of both sexes (middle age — 15 [14; 16] years) and underwent medical examination in the period from January 2021 to September 2022 were studied. All athletes were divided into 2 groups according to the presence of subclinical hypothyroidism (an increase in the level of thyroid-stimulating hormone from 5 to 10 mUn/l with a normal level of T4 free). During a dynamic follow-up (1 year), athletes with subclinical hypothyroidism underwent a repeated study of the concentration of thyroid-stimulating hormone, free thyroxine and antibodies to thyroperoxidase.Results: Signs of subclinical hyperthyroidism were found in 58 young athletes (30 boys (51.7 %) and 28 (48.3 %) girls). During dynamic observation with continued habitual physical activity, spontaneous normalization of the level of thyroid-stimulating hormone was observed in 74 % of young athletes. At the same time, normalization of thyroid-stimulating hormone in girls was observed less often compared to boys (p = 0,272). In no case did clinically pronounced hypothyroidism develop.Conclusion: The majority of young male and female athletes with subclinical hypothyroidism have spontaneous normalization of hormonal profile against the background of persistent physical and psycho-emotional stress. The data obtained make it possible, subject to the possibility of dynamic observation, to recommend doctors working with young elite athletes not to prescribe hormonal replacement therapy and not to modify the usual lifestyle.

Effects of the abdominal fat distribution on the relationship between exposure to air pollutants and thyroid hormones among Korean adult males

BackgroundSeveral significant associations between air pollution and thyroid function have been reported, but few studies have identified whether these associations differ by obesity, particularly its regional distribution. We assessed the relationship between ambient air pollution and thyroid hormone, and whether this relationship is modified by abdominal adiposity, as indicated by the waist circumference, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and visceral-to-subcutaneous fat ratio (VSR) in Korean men.MethodsWe included 2440 male adults in the final analysis and used each person’s annual average exposure to four air pollutants: particulate matter with an aerodynamic diameter ≤ 10 μm (PM10), nitrogen dioxide, sulfur dioxide (SO2), and carbon monoxide (CO). Abdominal fat deposition was quantified by computed tomography. Serum thyrotropin (TSH) and free thyroxine (FT4) concentrations were measured for thyroid hormone. To evaluate the relationship between air pollution and thyroid hormone according to adiposity, we performed multiple linear regression analysis on the two subgroups stratified by abdominal fat level.ResultsAbdominal adiposity was significantly related to FT4 concentration. The exposures to air pollutants were associated with increased TSH and decreased FT4 concentrations. In stratified analysis using abdominal fat traits, ambient air pollution except for SO2 was significantly related to increased TSH and decreased FT4 concentrations in the high adiposity group (all p < 0.05), but not in the normal adiposity group. Among the air pollutants, PM10 showed an association with an increase of TSH concentration in all group with high adiposity, including high VAT, high SAT, and high VSR groups (all p < 0.05). In case of FT4, CO showed a similar pattern. Among the abdominal fat-related traits, the VSR in the high adiposity group had the largest effect on the relationship between exposure to air pollutants and thyroid hormone.ConclusionsThis study suggests the first clue that the relationship between air pollution exposure and thyroid hormone differs according to abdominal fat distribution among Korean adult males.

Thyroid-Related Hormones Changes Predict Changes in Anthropometric Measures and Incidence of Obesity in Chinese Euthyroid Persons.

The purpose of this study was to investigate the correlation of thyroid-related hormones changes within the reference range with the changes in anthropometric measures and incidence of obesity. The study included 4850 subjects with normal thyroid-related hormones at baseline and at follow-up. We evaluated the relationship of changes in thyroid-related biomarkers with anthropometric measures changes and incidence of obesity. In euthyroid persons, changes in serum thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) concentrations and FT3/FT4 ratio were independent predictors of changes in body mass index (BMI) and waist circumference (WC) in men, changes in serum FT3 and FT4 concentrations and FT3/FT4 ratio were independent predictors of changes in BMI and WC in women. Every single unit increment in ΔFT3/FT4 was accompanied by a 7.144 and 7.572 times risk of having obesity in men and women, respectively. Every single unit decrement in ΔFT4 was accompanied by a 21.0% and 26.9% lower risk of having obesity in men and women, respectively. In conclusion, in euthyroid individuals, changes in thyroid-related hormones were associated with anthropometric measures changes and incidence of obesity.

Thyroid hormone-responsive protein mediates the response of chicken liver to fasting mainly through the cytokine-cytokine receptor interaction pathway

ABSTRACT 1. The objective of this study was to explore the mediating role of thyroid hormone-responsive protein (THRSP) in the response of chicken liver to fasting. 2. A batch of 7-d-old chicks with similar body weights were randomly divided into the control group and the fasting group (n = 10). The control group was fed ad libitum, while the test group fasted for 24 h. The liver and pectoral muscle tissues were collected. Chicken primary hepatocytes or myocytes were treated with different concentrations of thyroxine, glucose, insulin, oleic acid and palmitic acid, separately. Chicken primary hepatocytes were transfected with THRSP overexpression vector vs. empty vector, and the cells were used for transcriptome analysis. The mRNA expression of THRSP and other genes was determined by quantitative PCR. 3. The expression of THRSP in chicken liver and pectoral muscle tissues was significantly inhibited by fasting (P < 0.05). In chicken primary hepatocytes, the expression of THRSP was significantly induced by thyroxine (0.25, 0.5, 1 mmol/l), glucose (50, 100 mmol/l), and insulin (20 nmol/l), and was significantly inhibited by palmitic acid (0.125, 0.25 mmol/l). In the myocytes, expression of THRSP was significantly induced by thyroxine (0.25, 0.5, 1 mmol/l), glucose (50 mmol/l) and oleic acid (0.125, 0.25 mmol/l), was significantly inhibited by insulin (5 nmol/l) and was not significantly affected by palmitic acid. 4. Transcriptome analysis showed that overexpression of THRSP significantly affected the expression of 1411 DEGs, of which 1007 were up-regulated and 404 were down-regulated. The GO term and KEGG pathway enrichment analyses showed that these DEGs were mainly enriched in the interaction between cytokine and cytokine receptor and its regulation and signal transduction, cell growth and apoptosis and its regulation, immune response and retinol metabolism. 5. In conclusion, the THRSP gene mediates biological effects of fasting by influencing the expressional regulation of the genes related to biological processes such as cytokine-cytokine receptor interaction, cell growth and apoptosis, immune response, retinol metabolism, including TGM2, HSD17B2, RUNX3, IRF1, ANKRD6, UPP2, IKBKE, and PYCR1 genes, in chicken liver.

Urine concentrating ability in cats with hyperthyroidism: Influence of radioiodine treatment, masked azotemia, and iatrogenic hypothyroidism.

Hyperthyroid cats often have urine specific gravity (USG) values <1.035. It remains unclear how USG changes after treatment, if USG can be used to predict azotemia after treatment, or how iatrogenic hypothyroidism influences USG values. To determine the proportion of hyperthyroid cats with USG <1.035 vs ≥1.035; if USG changes after treatment; and whether USG <1.035 correlated with unmasking of azotemia or hypothyroidism. Six hundred fifty-five hyperthyroid cats treated with radioiodine; 190 clinically normal cats. Prospective, before-and-after study. Hyperthyroid cats had serum thyroxine, thyroid-stimulating hormone, and creatinine concentrations, and USG measured before and 6 months after successful treatment with radioiodine. Of untreated hyperthyroid cats, USG was ≥1.035 in 346 (52.8%) and <1.035 in 309 (47.2%). After treatment, 279/346 (80.6%) maintained USG ≥1.035, whereas 67/346 (19.4%) became <1.035; 272/309 (88%) maintained USG <1.035, whereas 37/309 (12%) became ≥1.035. Only 22/346 (6.4%) with USG ≥1.035 developed azotemia after treatment, compared with 136/309 (44%) with <1.035 (P < .001). Of cats remaining nonazotemic, 38% had USG <1.035, compared with 20% of normal cats (P < .001). The 137 cats with iatrogenic hypothyroidism had lower USG after treatment than did 508 euthyroid cats (1.024 vs 1.035), but USGs did not change after levothyroxine supplementation. USG <1.035 had high sensitivity (86.1%) but moderate specificity (65.2%) in predicting azotemia after treatment. Hyperthyroidism appears not to affect USG in cats. However, cats with evidence of sub-optimal concentrating ability before radioiodine treatment (USG < 1.035) are more likely to develop azotemia and unmask previously occult chronic kidney disease. Iatrogenic hypothyroidism itself did not appear to affect USG values.

Dietary hyperthyroidism in a dog with epileptic seizures

This report discusses a case of suspected dietary hyperthyroidism in a 2-year-old male crossbreed dog. The dog presented with a history of tonic-clonic seizures, seen over the previous 6 months, and was refractory to increasing doses of phenobarbitone. Serum total thyroxine concentrations were persistently elevated on repeated sampling; the rest of the investigations were normal. The initial diet – a raw food diet – was tested and found to contain detectable levels of total thyroxine. Dietary hyperthyroidism was therefore proposed as a potential cause of seizures in this case.

Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies

BackgroundPerfluoroalkyl substances (PFAS) and phthalates are synthetic chemicals widely used in various types of consumer products. There is epidemiological and experimental evidence that PFAS and phthalates may alter thyroid hormone levels; however, studies in children and adolescents are limited. AimTo investigate the association of exposure to PFAS and phthalate with serum levels of thyroid hormones in European adolescents. MethodsA cross-sectional study was conducted in 406 female and 327 male adolescents (14–17 years) from Belgium, Slovakia, and Spain participating in the Aligned Studies of the HBM4EU Project (FLEHS IV, PCB cohort, and BEA, respectively). Concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) were measured in sera from study participants, and urinary metabolites of six phthalates (DEP, DiBP, DnBP, BBzP, DEHP, and DiNP) and the non-phthalate plasticizer DINCH® were quantified in spot urine samples. Associations were assessed with linear regression and g-computational models for mixtures. Effect modification by sex was examined. ResultsIn females, serum PFOA and the PFAS mixture concentrations were associated with lower FT4 and higher FT3 levels; MEP and the sums of DEHP, DiNP, and DINCH® metabolites (∑DEHP, ∑DiNP, and ∑DINCH) were associated with higher FT4; ∑DEHP with lower FT3; and the phthalate/DINCH® metabolite mixture with higher FT4 and lower FT3. In males, PFOA was associated with lower FT4 and the PFAS mixture with higher TSH levels and lower FT4/TSH ratio; MEP and ∑DiNP were associated with higher FT4; and MBzP, ∑DEHP, and the phthalate/DINCH® metabolite mixture with lower TSH and higher FT4/TSH. PFOA, mono-(2-ethyl-5-hydroxyhexyl) phthalate (OH-MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (oxo-MEHP), and monocarboxyoctyl phthalate (MCOP) made the greatest contribution to the mixture effect. ConclusionsResults suggest that exposure to PFAS and phthalates is associated with sex-specific differences in thyroid hormone levels in adolescents.

Genetic determinants of thyroid function in children.

Genome-wide association studies in adults have identified 42 loci associated with thyroid stimulating hormone (TSH) and 21 loci associated with free thyroxine (FT4) concentrations. While biologically plausible, age-dependent effects have not been assessed. We aimed to study the association of previously identified genetic determinants of TSH and FT4 with TSH and FT4 concentrations in newborns and (pre)school children. We selected participants from three population-based prospective cohorts with data on genetic variants and thyroid function: Generation R (N = 2169 children, mean age 6 years; N = 2388 neonates, the Netherlands), the Avon Longitudinal Study of Parents and Children (ALSPAC; N = 3382, age 7.5 years, United Kingdom), and the Brisbane Longitudinal Twin Study (BLTS; N = 1680, age 12.1 years, Australia). The association of single nucleotide polymorphisms (SNPs) with TSH and FT4 concentrations was studied with multivariable linear regression models. Weighted polygenic risk scores (PRSs) were defined to combine SNP effects. In childhood, 30/60 SNPs were associated with TSH and 11/31 SNPs with FT4 after multiple testing correction. The effect sizes for AADAT, GLIS3, TM4SF4, and VEGFA were notably larger than in adults. The TSH PRS explained 5.3%-8.4% of the variability in TSH concentrations; the FT4 PRS explained 1.5%-4.2% of the variability in FT4 concentrations. Five TSH SNPs and no FT4 SNPs were associated with thyroid function in neonates. The effects of many known thyroid function SNPs are already apparent in childhood and some might be notably larger in children as compared to adults. These findings provide new knowledge about genetic regulation of thyroid function in early life.

Individual Features of the Hypothalamic-Pituitary-Thyroid Axis Functioning during Aging in Non-Human Primates.

Individual features of age-related changes in the function of the neuroendocrine systems are an important problem as the basic component of a personalized approach to predicting and treating age-related pathologies. We studied the age-related features of the function of the hypothalamic-pituitary-thyroid axis in laboratory primates with depression- and anxiety-like behavior (DAB). It was found that in young female rhesus monkeys with DAB, the basal and thyrotropin-releasing hormone-stimulated levels of thyroid-stimulating hormone were significantly lower than in young animals with standard behavior (control). During aging, the levels of thyroid-stimulating hormone increased in DAB animals and free thyroxine concentrations decreased both at baseline (fasting) and in response to the thyrotropin-releasing hormone test, while in animals with standard behavior, only a trend towards similar hormonal changes was revealed.

Influence of two anti-tumor drugs, pazopanib, and axitinib, on the development and thyroid-axis of zebrafish (Danio rerio) embryos/larvae.

In recent years, the potential toxicities of different pharmaceuticals toward the thyroid system have received increasing attention. In this study, we aim to evaluate the toxic effects of pazopanib and axitinib, two anti-tumor drugs with widespread clinical use, on thyroid function in the zebrafish model. We measured levels of thyroid-related hormones using the commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Whole-mount in situ hybridization (WISH) analysis was employed to detect target gene expression changes. Morphology of the thyroid were evaluated by using transgenic Tg (tg: EGFP) fish line under a confocal microscope. The relative mRNA expression of key genes was verified through quantitative real-time polymerase chain reaction (RT‒qPCR). The size and number of the follicles was quantified whereby Hematoxylin-Eosin (H & E) staining under a light microscope. The results revealed that fertilized zebrafish embryos were incubated in pazopanib or axitinib for 96 hours, development and survival were significantly affected, which was accompanied by significant disturbances in thyroid endocrine system (e.g., increased thyroid-stimulating hormone (TSH) content and decreased triiodothyronine (T3) and thyroxine (T4) content, as well as transcription changes of genes associated with the hypothalamus-pituitary-thyroid (HPT) axis. Moreover, based on whole-mount in situ hybridization staining of tg and histopathological examination of zebrafish embryos treated with pazopanib and axitinib, we observed a significantly abnormal development of thyroid follicles in the Tg (tg: EGFP) zebrafish transgenic line. Collectively, these findings indicate that pazopanib and axitinib may have toxic effects on thyroid development and function, at least partially, by influencing the regulation of the HPT axis. Thus, we believe that the potential thyroid toxicities of pazopanib and axitinib in their clinical applications should receive greater attention.

Submicroscopic changes of periodontal components under experimental periodontitis combined with hypothyroidism

Endocrine disorders are an extremely urgent medical and social problem of modern society. Changes in the thyroid gland activity cause violations of the regulation of metabolism in periodontal tissues. Expressed clinical signs of periodontal tissues inflammation directly depend on the severity and duration of disorders of the functional state of the thyroid gland. The purpose of this study was to describe the ultrastructural changes of periodontal tissues under the conditions of experimental periodontitis in combination with hypothyroidism. To model periodontitis lipopolysaccharide was injected into the gum tissue of rats. The experimental thyroid gland hypofunction was simulated using intragastrical administration of mercazolyl. To confirm the state of hypothyroidism we determined the content of free thyroxine, free triiodothyronine and thyroid-stimulating hormone. Submicroscopic studies revealed profound destructive-degenerative changes in all components of the periodontium. Changes in periodontal tissues in experimental hypothyroidism are stereotyped: dystrophic, atrophic and destructive changes in parenchymal structures, mucinous edema of the stroma, mild reparative processes. Thus, it can be concluded that during experimental periodontitis in combination with hypothyroidism, there are violations of the functioning of all the components of the vessels of the periodontal microcirculatory channel. This is manifested by damage and deformation of the blood vessel wall with desquamation of the endothelium, edema, thinning of the basement membrane, stasis, thrombosis and spasm. Also, significant destruction and lysis of fibrous structures and components of the connective tissue amorphous substance in the lamina propria of the attached and free part of gums and periodontium are characteristic.

Comparative assessment of the functional state of the thyroid gland and the adrenal cortex in cats of different ages

The study of the secretory activity of the endocrine glands is one of the main methods for assessing their functional state and the health of animals in general. In the experiment, we studied the activity of thyroid and corticosteroid hormones in 20 healthy cats aged 1 to 14 years of different breeds and sexes. In the blood serum of the experimental animals, the concentration of total and free thyroxine, total and free triiodothyronine, adrenocorticotropic hormone and cortisol was determined by the enzyme immunoassay. The results of the study showed that the concentration of thyroid and corticosteroid hormones in the blood serum of cats differs markedly depending on age. the functional activity of the adrenal cortex is maximal in cats aged 5 months to 1 year (first group). Thus, in comparison with this group, the level of ACTH in the blood serum of cats of the second group (1-3 years old) significantly decreased by 15.8% (p≤0.05), the third (3-6 years old) and the fourth (animals over 6 years old). ) by 37.7 and 22.1%, respectively (p≤0.01). Also revealed a significant decrease in the concentration of cortisol in animals in the third and fourth groups by 22.1 and 26.8%, respectively, compared with the first group (p≤0.01). The least functional activity of the thyroid gland and adrenal cortex is observed in cats aged 6 years and older. The greatest functional activity of the adrenal cortex is observed in cats aged from 5 months to 1 year. The data obtained make it possible to more effectively detect disorders in the functioning of the thyroid and adrenal glands in animals, taking into account age-related changes.

Evaluation of cortisol, thyroxine (T3) and triiodothyronine (T4) concentrations in preovulatory follicles in jennies.

Reference values of follicular fluid components at different stages of follicular development in jennies are unknown. It is important to estimate such values because the biochemical composition of follicular fluid provides a suitable microenvironment for oocyte development, growth and maturation. The experimental protocol was carried out in the Equine Reproduction Clinic of the FMVZ-UNAM and was approved by an Institutional Sub-committee for the Care and Use of Experimental Animals (SICUAE.MMVZ-2020/4-2). Seven healthy female donkeys “Mexican burro” with average body condition score of 3 on a scale of 1 to 5 (Svendsen et al. The professional Handbook of the Donkey. 2008), were monitored by transrectal ultrasonography through the Veterinary Digital Diagnostic Ultrasound System 5 MHz (Model, DUS 60 VET) with a multi-frequency linear transducer. The ovum pick up (OPU) by transvaginal aspiration (TVA) was performed in a total of 70 preovulatory follicles, 10 for each jenny using a real- time B- mode ultrasound vaginal 6.5 MHz (Sonovet 600) with curvilinear transducer and 12 gauge (12 G) needle. Follicular fluid components were measured and analyzed by Luminex Multiplex Assays at the Universidad Nacional Autónoma de México. The relationship between cortisol, thyroxine (T3) and triiodothyronine (T4) concentrations in preovulatory follicles and follicular size was assessed. The preovulatory follicles are classified in three groups accordingto the diameter: small (27-30 mm), medium (31-35 mm) and large (36-38 mm). Concentrations of cortisol were lower in the large follicles group (18.8 ng/ml) compared with small (721.44 ng/ml) and medium follicles (361 ng/ml). The concentrations of thyroxine were higher in the medium follicle group (49 ng/ml) than in the small (21ng/ml) and large follicle groups (15.9 ng/ml). Finally, the concentration of triiodothyronine was higher in the small follicles group (1043 ng/ml) followed by the medium (545 ng/ml) and the lowest concentration was in the large follicles group (22 ng/ml). It is concluded that thyroxine concentrations are lower than T4 concentrations in preovulatory follicles irrespective of size as reported for human follicular fluid (Wakim. et. al. Fertil Steril 1993; 59(6) 1187–1190). Furthermore, no relationship was found between preovulatory follicular size and thyroxine hormone concentrations. It has been suggested that cortisol and triiodothyronine concentrations are related to preovulatory follicle size. Cortisol concentrations are higher in preovulatory follicles that in subordinate follicles and cortisol is a mediator of apoptosis in granulosa cells, differentiation, development and maturation of tissues, specifically in the oocyte (Acosta & Miyamoto. Anim Reprod Sci 2004; 82:127-140, Scarlett. et al. Dom Anim Endocrinol 2016; 59:11-22). The role of cortisol within the different sizes of preovulatory follicles is unknown.

Plasma metabolic profiling reveals that chromium yeast alleviates the negative effects of heat stress in mid-lactation dairy cows.

Chromium yeast (CY) supplementation has the potential to alleviate the negative effects of heat stress in dairy cows, but the mechanism remains elusive. We aimed to identify the metabolic mechanisms whereby CY supplementation alleviates the negative effects of heat stress in mid-lactation dairy cows. Twelve Holstein dairy cows with similar milk yield (24.6±1.5kg/d), parity (2 or 3) and days in milk (125±8d) were fed the same basal diet containing 0.09mg of Cr/kg DM. They were allocated randomly to 2 groups: a control group (CON, without CY supplementation) and a CY group (CY, administered 0.36mg Cr/kg DM). The experiment was performed over 8 weeks during a hot summer, in which the mean temperature-humidity index was 79.0±3.13 (>72), indicating that the dairy cows were exposed to heat stress. Chromium yeast supplementation reduced rectal temperature (P=0.032), and increased the lactation performance by increasing the yield of milk (+2.6kg/d), protein, lactose and total solid, and protein and lactose percentages in the milk of the heat-stressed dairy cows (P<0.05). Supplementation with CY increased the serum glucose and thyroxine concentrations, but reduced the urea nitrogen, insulin, and triiodothyronine concentrations on d 56 (P<0.05). Furthermore, plasma metabolomic analysis was performed using liquid chromatography tandem-mass spectrometry, which identified 385 metabolites in the two groups. Subsequently, 16 significantly different metabolites in the plasma, were significantly higher in the CY group (variable importance for the projection >1.0, P<0.05), and found to be involved in 6 Kyoto Encyclopedia of Genes and Genomes pathways, including those involved in nicotinate and nicotinamide metabolism. Specifically, plasma concentration of nicotinamide was higher after CY supplementation, which might also contribute to the reduction of rectal temperature, the regulation of glucose homeostasis, and an improvement in the lactation performance of heat-stressed dairy cows. In conclusion, CY supplementation reduces rectal temperature, influences metabolism by reducing serum insulin concentration and increasing serum glucose and plasma nicotinamide concentrations, and finally increases lactation performance of heat-stressed dairy cows.

Decreased neurokinin B as a risk factor of functional hypothalamic amenorrhea

Background Neurokinin B (NKB) belongs to the tachykinin family of proteins who’s regulation is essential for proper function of the reproductive system. It has been shown that patients with functional hypothalamic amenorrhea (FHA) exhibit decreased levels of serum kisspeptin. As kisspeptin secretion is regulated by NKB signaling, it is reasonable to suspect that patients with FHA will also have abnormal NKB secretion. Aim To assess NKB levels in patients with FHA and to determine whether NKB signaling is affected in these patients. We hypothesized that decreased NKB signaling is a factor contributing to the development of the FHA. Materials and methods A total of 147 patients with FHA and 88 healthy age-matched controls were enrolled. Baseline blood samples were drawn from both groups to measure serum concentrations of NKB, luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), prolactin (PRL), thyroid-stimulating hormone (TSH), free thyroxine (fT4), cortisol, dehydroepiandrosterone sulfate (DHEA-S), testosterone (T), glucose, and insulin. Results Mean serum NKB levels were found to be decreased significantly in the FHA group when compared with the control group (628.35 ± 324.92 vs. 721.41 ± 337.57 ng/L, respectively p = 0.002). No statistical difference was observed in NKB-1 levels within the FHA group when selecting for normal and decreased body mass index. Conclusions Patients with FHA were found to have decreased serum NKB concentrations when compared to healthy controls. Abnormal NKB secretion is likely a key factor contributing to development of FHA.