Thyroid hormone concentrations in the plasma of fed and fasted Brahman and Hereford steers

1994 ◽  
Vol 34 (4) ◽  
pp. 439
Author(s):  
JC O'Kelly ◽  
WG Spiers
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Free T4 ◽  
Rumen Metabolism ◽  
Body Tissues ◽  
Breed Differences ◽  
Feeding Regimes ◽  
Ad Libitum ◽  
Brahman Steers

Plasma concentration patterns of thyroxine (TJ, free T4 (FT4), triiodothyronine (T3), and free T3 (FT3) were determined in Brahman steers fed lucerne hay ad libitum and in Brahman and Hereford steers fed restricted intakes of lucerne hay at the rate of either 208 g/h before fasting for 72 h or 250 g/h before fasting for 96 h. In Brahmans fed ad libitum, the plasma concentrations of all thyroid hormone fractions were significantly (P<0.01) correlated with one another and with feed intake. Within breeds, the concentrations of thyroid hormones were higher (P<0.001) when animals were fed at 250 g k than at 208 g/h. During both hourly feeding regimes T4, FT4, T3, and FT3 concentrations were higher (P<0.001) in Brahmans than in Herefords. Fasting after both hourly feeding regimes lowered (P<0.001) the concentrations of T4 about 53% in Brahmans and 30% in Herefords, while FT4, T3, and FT3 were lowered about 68% in Brahmans and 50% in Herefords. Consequently, thyroid hormone concentrations were significantly lower in Brahmans than in Herefords after 72 h fasting but did not differ significantly between breeds after 96 h fasting. The present results, together with those of our previous work showing breed differences in rumen metabolism, support the concept that, in Hereford and Brahman steers fed the same amount of hay in a thermoneutral environment, breed differences in plasma concentrations of thyroid hormones originate from quantitative differences in the supply of nutrients from the rumen to body tissues.

Influence of monensin on some metabolic responses of cattle fed a restricted intake of lucerne hay during heat exposure

1991 ◽  
Vol 31 (3) ◽  
pp. 301
Author(s):  
JC O'Kelly
Keyword(s):  
Body Temperature ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Heat Exposure ◽  
Ruminal Fermentation ◽  
Free T4 ◽  
Metabolic Derangement ◽  
Normal Body Temperature ◽  
Ruminal Fluid ◽  
Brahman Steers

The effects of monensin supplement (33 mg/kg feed) on ruminal fermentation and body metabolism were studied in Brahman steers fed 5 kg lucerne hay daily at thermoneutral temperature (24�C) and after heat exposure [I day at 31�C (acute) or 5 days at 37�C (chronic)]. At 24�C, monensin lowered the concentrations of ammonia and protozoa in ruminal fluid and increased the plasma concentration of cholesterol but did not affect the circulating levels of urea, glucose, insulin, thyroxine (T4), triiodothyronine (T3), free T4 and free T3. Acute heat exposure lowered the plasma concentrations of thyroid hormones. Chronic heat exposure increased body temperature, the rate of dry matter digestion in the rumen and urinary nitrogen and allantoin excretion and lowered the plasma concentrations of cholesterol and differentially lowered the concentrations of the thyroid hormones. An increase in the concentration of ammonia in ruminal fluid was the only response to monensin at elevated body temperature that was uncharacteristic of its effects at normal body temperature. The results indicate that a monensin treatment of 33 mg/kg feed does not have any adverse effects on steers suffering metabolic derangement during hyperthermia.

Manipulation of thyroid hormones in ruminants - a tool to understand their physiological role and identify their potential for increasing production efficiency

2002 ◽  
Vol 53 (3) ◽  
pp. 259 ◽  
Author(s):  
D. Villar ◽  
S. M. Rhind ◽  
J. R. Arthur ◽  
P. J. Goddard
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Production Efficiency ◽  
Hormone Replacement ◽  
Animal Health ◽  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Physiological Role ◽  
Antithyroid Drugs ◽  
Few Data

Manipulations of thyroid hormone secretion and function can be used to cure thyroidal deficiencies or overactivity and as a tool to investigate their physiological roles and identify potential protocols for enhancing animal performance. An essential approach to the investigation of thyroid hormone action involves the induction of hypothyroidal states. Methods of inducing hypothyroidal states in ruminants include thyroidectomy and treatment with thionamides. There are few data concerning the induction of an optimal degree of hypothyroidism for the study of thyroid function in ruminants, unlike the situation in rodents. The effects of hypothyroidism on the physiology of ruminants, and the relative merits of thyroidectomy or of treatment with thionamides to manipulate thyroid hormone profiles in them, are reviewed and discussed. Thyroidectomy in ruminants induces an acute, irreversible, hypothyroidal state. It also has indirect, predominantly adverse, effects on many physiological processes and impairs health. Thus, thyroidectomised (THX) animals cannot be sustained for long-term studies without thyroid hormone replacement. Antithyroid drugs of the thionamide class, on the other hand, have been used with success to induce varying degrees of hypothyroidism, predominantly less severe than those induced by thyroidectomy. The changes induced by drugs are reversible upon withdrawal of treatment. However, treatment may require daily administration of the drug for several weeks before stable plasma concentrations of thyroid hormone are achieved. Furthermore, at high doses, these drugs can have toxic side effects. It is concluded that the treatment regime of choice will depend on the objectives of the individual study. Knowledge of the activities of thyroid hormone metabolising, deiodinase enzymes in the target tissues is also required if the actions of some of these drugs, their physiological roles in modulation of the thyroid hormones, and, crucially, their potential effects on animal health and production are to be properly understood and exploited.

THYROID PROFILE IN CHILDREN WITH NEPHROTIC SYNDROME

2021 ◽  
pp. 75-77
Author(s):  
Meiyappan Kavitha ◽  
Mallaiyan Manonmani
Keyword(s):  
Nephrotic Syndrome ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Thyroid Stimulating Hormone ◽  
The Body ◽  
Urinary Protein ◽  
Creatinine Ratio ◽  
Free Triiodothyronine ◽  
Free T4 ◽  
Renal Disorder

Objectives: Nephrotic syndrome is a common renal disorder seen in children, with proteinuria as the hallmark. Growth retardation is a known feature of nephrotic syndrome, either due to the disease or treatment with steroids. Thyroid hormone strongly inuences growth of the body. So, the present study was undertaken with the objective to assess the thyroid prole in children with nephrotic syndrome Methods: The study involved 41 cases of nephrotic syndrome and 41 age and sex matched controls. Serum total triiodothyronine (T3), total thyroxine (T4), free triiodothyronine (T3), free thyroxine (T4) and thyroid stimulating hormone (TSH) were assessed in these subjects. The thyroid hormones were correlated with urinary protein creatinine ratio. The cases were followed up after one month and the levels of thyroid hormones were reassessed. Results: Total T3, total T4, free T3 and free T4 are signicantly decreased and TSH signicantly increased among cases when compared to controls. TSH is positively correlating with urinary protein creatinine ratio in cases. After one month of treatment, total T3 and total T4 are signicantly increased in cases. Conclusions: The thyroid hormone levels are altered in children with nephrotic syndrome during the episode. A state of subclinical hypothyroidism exists during the nephrotic stage. The alteration is normalized with remission and does not require treatment.

Possible contribution of protozoa to differences in rumen metabolism between cattle breeds

1992 ◽  
Vol 43 (8) ◽  
pp. 1795 ◽  
Author(s):  
JC O'Kelly ◽  
WG Spiers
Keyword(s):  
Fatty Acids ◽  
Population Density ◽  
Volatile Fatty Acids ◽  
Essential Fatty Acids ◽  
Plasma Concentrations ◽  
Metabolizable Energy ◽  
Rumen Temperature ◽  
Once Daily ◽  
Rumen Metabolism ◽  
Body Tissues

Brahman (B) and Hereford (H) cattle were used to study protozoal population density of ruminal fluid (RF) in relation to some aspects of rumen and body metabolism. Steers were fed restricted intakes of lucerne hay (HQ) or low-quality hay (LQ) in each of eight experiments. In the 8 h period following the once-daily feeding of HQ the number of entodiniomorphs declined by 50%, while the number of holotrichs increased by 60% before reducing to pre-feeding levels. There were no significant rises and falls in the numbers of protozoa of steers fed LQ once daily nor in those fed either HQ or LQ at hourly intervals. The numbers of entodiniomorphs, dasytrichs, total protozoa, pH and bacterial content of RF were higher and rumen temperature lower in B than in H. Urinary allantoin excretion used as an index of the total microbial population in the rumen distinguished between diets but not between breeds. The concentrations of propionic, butyric, isobutyric and isovaleric acids in RF and of glucose in plasma were higher in B than in H. The concentrations of all classes of long-chain fatty acids contained in the protozoa and bacteria of RF and of cholesterol and essential fatty acids in plasma were higher in B than in H. The amount of dry matter disappearing from nylon bags in the rumen of steers fed HQ did not differ between breeds, but was higher in B than in H fed LQ. Elevation of pH to peak values in RF with an accompanying disappearance of protozoa and volatile fatty acids during fasting from either HQ or LQ occurred more rapidly in B than in H. The plasma concentrations of non-esterified fatty acids were higher in B than in H during fasting. It is proposed that at the same level of intake of either HQ or LQ: (1) the higher protozoal population density in RF of B contributes to quantitative breed differences in the end products of digestion, (2) that B achieve and maintain a higher body weight because more metabolizable energy and essential nutrients are supplied from the rumen to their body tissues, and (3) after the same period of feed deprivation B have fasted for a longer period of time because the residual feed in their rumens is fermented at a more rapid rate.

scholarly journals Thyroid Hormones Decrease Plasma 1α,25-Dihydroxyvitamin D Levels Through Transcriptional Repression of the Renal 25-Hydroxyvitamin D3 1α-Hydroxylase Gene (CYP27B1)

Endocrinology ◽  
2013 ◽  
Vol 154 (2) ◽  
pp. 609-622 ◽  
Author(s):  
Mina Kozai ◽  
Hironori Yamamoto ◽  
Mariko Ishiguro ◽  
Nagakatsu Harada ◽  
Masashi Masuda ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Gene Transcription ◽  
Transcriptional Repression ◽  
Transcriptional Activity ◽  
Plasma Concentrations ◽  
Mrna Levels ◽  
Dihydroxyvitamin D ◽  
Low Calcium Diet ◽  
Low Calcium

The primary determinant of circulating 1α,25-dihydroxyvitamin D (1,25[OH]2D) levels is the activity of 25-hydroxyvitamin D-1α-hydroxylase (cytochrome P450 27B1 [CYP27B1]) in the kidney. Hyperthyroid patients have been reported to have low levels of plasma 1,25(OH)2D. However, the detailed mechanism of thyroid hormone action on vitamin D metabolism is still poorly understood. The present study determined whether renal CYP27B1 gene expression was negatively regulated by thyroid hormones. T3-induced hyperthyroid mice showed marked decreases in plasma 1,25(OH)2D levels and in renal expression of CYP27B1 mRNA but no changes in plasma concentrations of calcium, PTH, or fibroblast growth factor-23. In addition, we observed that T3 administration significantly decreased plasma 1,25(OH)2D and renal CYP27B1 mRNA levels that were increased by low-calcium or low-phosphorus diets and induced hypocalcemia in mice fed a low-calcium diet. Promoter analysis revealed that T3 decreases the basal transcriptional activity of the CYP27B1 gene through thyroid hormone receptors (TRα and TRβ1) and the retinoid X receptor α (RXRα) in renal proximal tubular cells. Interestingly, we identified an everted repeat negative thyroid hormone response element (1α-nTRE) overlapping the sterol regulatory element (1α-SRE) and the TATA-box −50 to −20 base pairs from the human CYP27B1 gene transcription start site. Finally, we established that CYP27B1 gene transcription is positively regulated by SRE-binding proteins and that a T3-bound TRβ1/RXRα heterodimer inhibits SRE-binding protein-1c-induced transcriptional activity through the 1α-nTRE. These results suggest that transcriptional repression of the CYP27B1 gene by T3-bound TRs/RXRα, acting through the 1α-nTRE, results in decreased renal CYP27B1 expression and plasma 1,25(OH)2D levels.

scholarly journals Thyroid Hormone Concentrations, Disease, Physical Function, and Mortality in Elderly Men

2005 ◽  
Vol 90 (12) ◽  
pp. 6403-6409 ◽  
Author(s):  
Annewieke W. van den Beld ◽  
Theo J. Visser ◽  
Richard A. Feelders ◽  
Diederick E. Grobbee ◽  
Steven W. J. Lamberts
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Physical Function ◽  
Grip Strength ◽  
High Serum ◽  
Healthy Adults ◽  
Elderly Men ◽  
Normal Range ◽  
Free T4 ◽  
Low T3

Context: Physiological changes in thyroid hormone concentrations might be related to changes in the overall physical function in the elderly. Objective: We determined to what extent thyroid hormone concentrations are related to physical function and mortality in elderly men. Design: A longitudinal population study (the Zoetermeer study) was conducted. Mortality was registered in the subsequent 4 yr. Participants: Four hundred three independently and ambulatory living men (aged 73–94 yr) participated. Main Outcome Measures: The study examined the association between serum thyroid hormones and parameters of physical function as well as the association with mortality. Methods: TSH, free T4 (FT4) total T4, T3, rT3, and T4-binding globulin were measured. Physical function was estimated by the number of problems in activities of daily living, a measure of physical performance score (PPS), leg extensor strength and grip strength, bone density, and body composition. Results: Serum rT3 increased significantly with age and the presence of disease. Sixty-three men met the biochemical criteria for the low T3 syndrome (decreased serum T3 and increased serum rT3). This was associated with a lower PPS, independent of disease. Furthermore, higher serum FT4 (within the normal range of healthy adults) and rT3 (above the normal range of healthy adults) were related with a lower grip strength and PPS, independent of age and disease. Isolated low T3 was associated with a better PPS and a higher lean body mass. Low FT4 was related to a decreased risk of 4-yr mortality. Conclusions: In a population of independently living elderly men, higher FT4 and rT3 concentrations are associated with a lower physical function. High serum rT3 may result from a decreased peripheral metabolism of thyroid hormones due to the aging process itself and/or disease and may reflect a catabolic state. Low serum FT4 is associated with a better 4-yr survival; this may reflect an adaptive mechanism to prevent excessive catabolism.

scholarly journals Evaluation of thyroid status in patients with thyrotoxicosis

1996 ◽  
Vol 42 (1) ◽  
pp. 174-178 ◽  
Author(s):  
L E Braverman
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pituitary Tumors ◽  
Clinical Syndrome ◽  
Thyroid Peroxidase ◽  
Free T4 ◽  
Serum Thyroglobulin ◽  
Autoimmune Thyroid ◽  
Resistance To Thyroid Hormones ◽  
Autonomously Functioning Thyroid Nodules

Abstract The generic term thyrotoxicosis defines the clinical syndrome of hypermetabolism associated with excess amounts of circulating free thyroxine (T4) and (or) triiodothyronine (T3) concentrations, irrespective of the source of the excess hormones. The term hyperthyroidism is reserved for those patients with thyrotoxicosis caused by increased synthesis and secretion of thyroid hormones from the gland due either to thyroid stimulators in the blood or to autonomously functioning thyroid nodules and is almost always associated with an increased radioactive iodine uptake (RAIU) by the thyroid. Another major cause of thyrotoxicosis is increased release of thyroid hormone from the gland, not associated with increased synthesis, caused by inflammatory changes, and always associated with a low thyroid RAIU. The most common miscellaneous cause of thyrotoxicosis is the exogenous ingestion of excess thyroid hormone, associated with a low thyroid RAIU. The serum concentration of thyrotropin (TSH) is low in all causes of thyrotoxicosis, except for TSH-secreting pituitary tumors and selective pituitary resistance to thyroid hormones. Anti-thyroglobulin and anti-thyroid peroxidase antibodies are present in patients with autoimmune thyroid disease, and serum thyroglobulin is increased in all patients with thyrotoxicosis except those with thyrotoxicosis facticia. A decreased serum TSH and normal concentrations of serum free T4 and T3 define the syndrome of subclinical thyrotoxicosis.

scholarly journals Applicability of thyroxine measurements and ultrasound imaging in evaluations of thyroid function in turtles

2019 ◽  
Vol 63 (2) ◽  
pp. 267-273
Author(s):  
Joanna Pajdak-Czaus ◽  
Elżbieta Terech-Majewska ◽  
Dagmara Będzłowicz ◽  
Martyn Mączyński ◽  
Wioletta Krystkiewicz ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Thyroid Function ◽  
Ultrasound Imaging ◽  
Ultrasound Examination ◽  
Plasma Concentrations ◽  
Physiological Homeostasis ◽  
Low Levels ◽  
And Function

AbstractIntroduction: The thyroid and parathyroid glands play a major role in maintaining physiological homeostasis in all vertebrates. Reptiles have plasma concentrations of thyroid hormones far lower than mammals. Low levels of these hormones in reptiles impede thyroid hormone detection with assays designed for the higher levels of mammals. The aim of this study was to explore teaming this with ultrasound imaging of the thyroid to appraise glandular function. Material and Methods: Thyroid function of four pond sliders was evaluated based on the results of T4 analyses and ultrasound. Results: The concentrations of T4 varied considerably between the examined animals from <9 nmol/L to >167.3 nmol/L. Ultrasound examination revealed uniform echogenicity and a smooth outline of the thyroid gland in all animals. Conclusion: Monitoring of thyroid function based on T4 and electrolyte concentrations is helpful in assessing the health and living conditions of reptiles, which is important in veterinary practice but problematic. Ultrasound examinations are useful in diagnosing changes in gland structure, such as tumours and goitres, and a combination of both methods supports comprehensive assessments of the anatomy and function of the thyroid gland.

scholarly journals Alterations in endothelium-associated proteins and serum thyroid hormone concentrations in anorexia nervosa

1992 ◽  
Vol 68 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Gen Komaki ◽  
Hajime Tamai ◽  
Toshio Mukuta ◽  
Nobuyuki Kobayashi ◽  
Kenji Mori ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Weight Gain ◽  
Thyroid Hormone ◽  
Plasma Concentrations ◽  
Free T4 ◽  
Free T3 ◽  
Before And After ◽  
Associated Proteins ◽  
Serum T3 ◽  
Serum Thyroid Hormone

Plasma concentrations of endothelium-associated proteins (EAP) (plasma fibronectin (PFN), angio-tensin-converting enzyme, factor VIII-related antigen (F VIII-R:Ag)) and tissue plasminogen activator and serum thyroid hormone concentrations were studied in nine patients with anorexia nervosa (AN), before and after weight gain. Before weight gain (-35.9 (se 2.3)% of standard body-weight) PFN was significantly reduced and F VIII-R:Ag was significantly increased in AN patients compared with the concentrations in control subjects (211.5 (se 14.9)v.274.7 (se 16.6) μg/ml,P< 0.05; 129.2 (se 14.1)v.88.2 (se 9.7)%,P<0.05 respectively). Serum triiodothyronine (T3) and free T3 levels were also significantly lower before weight gain in AN patients (0.85 (se 0.07)v.1.53 (se 0.08) nmol/l,P< 0.001; 2.57 (se 0.23)v.5.31 (se 0.34) pmol/l,P< 0.001 respectively), although serum thyroxine (T4), free T4, and thyrotropin concentrations were within the normal range throughout the study periods. Following weight gain, PFN and F VIII-R: Ag concentrations normalized as did the thyroid hormone levels. The incremental changes in PFN levels correlated significantly with those in serum thyroid hormone concentrations (T3,r0.79,P<0.01; free T3,r0.84,P< 0.01). These findings suggest that PFN levels may be directly related to serum T3 concentrations in AN patients.

scholarly journals Unravelling the role of thyroid hormones in seasonal neuroplasticity in European Starlings (Sturnus vulgaris)

2021 ◽  
Author(s):  
Jasmien EMJ Orije ◽  
Sander R Raymaekers ◽  
Gaurav Majumadar ◽  
Geert De Groof ◽  
Elisabeth Jonckers ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Active Role ◽  
Fine Tuning ◽  
European Starlings ◽  
Photosensitive Period ◽  
Song Control

Thyroid hormones clearly play a role in the seasonal regulation of reproduction, but any role they might play in song behavior and the associated seasonal neuroplasticity in songbirds remains to be elucidated. To pursue this question, we first established seasonal patterns in the expression of thyroid hormone regulating genes in male European starlings employing in situ hybridization methods. Thyroid hormone transporter LAT1 expression in the song nucleus HVC was elevated during the photosensitive phase, pointing towards an active role of thyroid hormones during this window of possible neuroplasticity. In contrast, DIO3 expression was high in HVC during the photostimulated phase, limiting the possible effect of thyroid hormones to maintain song stability during the breeding season. Next, we studied the effect of hypothyroidism on song behavior and neuroplasticity using in vivo MRI. Hypothyroidism inhibited the photostimulation-induced increase in testosterone, confirming the role of thyroid hormones in activating the hypothalamic-pituitary-gonadal (HPG) axis. Surprisingly, apart from the myelination of several tracts during the photostimulated phase, most neuroplasticity related to song production was unaffected by hypothyroidism. Remarkably, T3 plasma concentrations were negatively correlated to the microstructural changes in several song control nuclei. Potentially, a global reduction of circulating thyroid hormones during the photosensitive period is necessary to lift the brake imposed by the photorefractory period, whereas local fine-tuning of thyroid hormone concentrations through LAT1 could activate underlying neuroplasticity mechanisms. Given the complexity of thyroid hormone effects, this study is a steppingstone to disentangle the influence of thyroid hormones on seasonal neuroplasticity.

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