Search results for "Triiodothyronine"
showing 10 items of 57 documents
Is maternal thyroid hormone deposition subject to a trade-off between self and egg because of iodine?
2021
ABSTRACT Maternal hormones constitute a key signalling pathway for mothers to shape offspring phenotype and fitness. Thyroid hormones (THs; triiodothyronine, T3; and thyroxine, T4) are metabolic hormones known to play crucial roles in embryonic development and survival in all vertebrates. During early developmental stages, embryos exclusively rely on exposure to maternal THs, and maternal hypothyroidism can cause severe embryonic maldevelopment. The TH molecule includes iodine, an element that cannot be synthesised by the organism. Therefore, TH production may become costly when environmental iodine availability is low. This may yield a trade-off for breeding females between allocating the …
Changes in body mass and hormone levels between wintering and spring staging areas in Dark-bellied brent geese Branta bernicla bernicla
2006
International audience; Wintering migratory geese generally replenish protein stores lost during migration before building up their fat stores (Gauthier et al. 1992). Dark-bellied brent geese Branta bernicla bernicla winter mainly along the coasts of France, England and the south-western part of the Netherlands, and stage from March till late May mainly in the Wadden Sea, stretching from the northern Netherlands to Denmark (Ebbinge et al. 1999). During spring, geese accumulate body stores needed both for their long-distance migration to the breeding grounds and for reproduction (Spaans et al. 1993, Ebbinge and Spaans 1995). Dark-bellied brent geese, migrating about 5000 km between the winte…
Effects of 3,5-diiodo-L-thyronine on the liver of high fat diet fed rats
2016
Experimental studies have highlighted that the administration of 3,5-diiodo-L-thyronine (T2) to rats fed diets rich in lipids induces a decrease of cholesterol and triglycerides plasma levels and body weight (BW) without inducing liver steatosis. On the basis of these observations we carried out some experimental <em>in vivo</em> studies to assess the effects of multiple high doses of T2 on the pituitary thyroid axis of rats fed diet rich in lipids. Fifteen male Wistar rats were divided into three groups of five animals each. The first group (N group) received standard diet, the second group was fed with a high fat diet (HFD group), while the third group (HFDT2 group) was additi…
Exposure to perfluoroalkyl substances and thyroid function in pregnant women and children: A systematic review of epidemiologic studies
2017
Introduction: Thyroid hormones (THs) are especially important for brain maturation and development during the fetal period and childhood. Several epidemiological studies have assessed the possible association between exposure to perfluoroalkyl substances (PFAS) and thyroid outcomes during the early stages of life. We aimed to review this evidence. Methods: We conducted a systematic review in compliance with the PRISMA Statement (search conducted in PubMed and Embase, as well as in the citations of the selected articles). We chose studies if they dealt with thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxin (T4), or thyroid dysfunctions, and perfluorohexane sulfonate (PFHxS),…
Maternal Perfluoroalkyl Substances, Thyroid Hormones, and DIO Genes: A Spanish Cross-sectional Study
2021
Results of studies on perfluoroalkyl substances (PFASs) and thyroid hormones (THs) are heterogeneous, and the mechanisms underlying the action of PFASs to target THs have not been fully characterized. We examined the relation between first-trimester maternal PFAS and TH levels and the role played by polymorphisms in the iodothyronine deiodinase 1 (DIO1) and 2 (DIO2) genes in this association. Our sample comprised 919 pregnant Spanish women (recruitment = 2003-2008) with measurements of perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), thyroid-stimulating hormone (TSH), total triiodothyronine (TT3), and fr…
Correlation between different degree and duration of metabolic control and thyroid hormone levels in type 1 and type 2 diabetics.
1983
Thyroxine (T4), triiodothyronine (T3), reverse T3 (rT3) and HbA1c were assayed in 21 insulin-dependent (type 1) diabetics and in 45 non-insulin-dependent (type 2) diabetics with normal thyroid function and different levels of control, and were compared to values found in apparently healthy controls. rT3 and rT3/T3 ratio were significantly increased both in type 1 and type 2 diabetics. T3 and T4 were significantly lower in type 2 diabetics than in the controls. Significant positive correlations of HbA1c to rT3 (r = 0.63) and to rT3/T3 ratio (r = 0.53) were found in type 1, and in type 2 diabetics (HbA1c, rT3-r = 0.50), (HbA1c, rT3/T3-r = 0.37). There was no correlation between glycemia (BG),…
Alterations in circadian rhythm of serum thyrotropin in critically ill patients.
1992
To evaluate the 24-h pattern of serum thyrotropin (TSH) in critically ill patients, we measured serum concentrations of TSH in blood samples collected every 2 h for 24 h from nine patients (six with malignancy, two with liver cirrhosis, one with chronic renal failure), who had subnormal levels of both triiodothyronine (T3) and thyroxine (T4), in the absence of history, symptoms or signs of thyroid disease. Analysis of the data, performed using a second-order inferential statistical methodology for rhythmometry (cosinor method), demonstrated that critically ill patients still had daily oscillations of serum TSH which significantly adapted to the function approximating the circadian rhythms (…
The prognostic value of thyroid function tests in predominantly non-alcoholic cirrhotic patients: A prospective investigation
1985
The prognostic value of thyroid function parameters (T3, T4, rT3 and the rT3: T3 ratio) and common liver tests (serum bilirubin, albumin and prothrombin activity) was investigated on hospital admission in 100 consecutive patients with predominantly non-alcoholic liver cirrhosis. Twenty-nine out of 100 patients had a well compensated cirrhosis and their mean values of thyroid tests were similar to those of 40 healthy controls. A low T3 syndrome was found in the remaining 71 decompensated patients. In these thyroid function parameters were correlated with serum bilirubin and prothrombin activity. Moreover mean values of all thyroid and liver tests, except serum albumin, were significantly dif…
Deficient pulsatile thyrotropin secretion in the low-thyroid-hormone state of severe non-thyroidal illness
1994
Custro N, Scafidi V, Gallo S, Notarbartolo A. Deficient pulsatile thyrotropin secretion in the low-thyroid-hormone state of severe non-thyroidal illness. Eur J Endocrinol 1994;130:132–6. ISSN 0804–4643. Twenty-four-hour thyrotropin (TSH) profiles in eight severely ill patients were compared with those of six healthy subjects. The profiles were assessed using the cosinor method to evaluate circadian variations and using the Pulsar algorithm to analyze episodic secretion. In the normal subjects, the typical periodicity of TSH secretion showed a mean level in the rhythm (mesor) of 2.03 mU/l, The amplitude (half the extent of rhythmic change in the cycle) was 0.58 mU/l; the acrophase (the delay…
Impact of a 4-Week Intensified Endurance Training Intervention on Markers of Relative Energy Deficiency in Sport (RED-S) and Performance Among Well-T…
2020
Cyclists often apply block periodization to high training volumes in meso- and macrocycles to optimize training adaptation and to prepare for competition. Body mass influences performance in many sports, including endurance disciplines, and conditions related to the syndrome Relative Energy Deficiency in Sports (RED-S) such as metabolic adaptations and premature osteoporosis have also been reported in male cyclists. This study aimed to determine how a 4-week mesocycle of intensified endurance training designed to increase performance, would affect markers of RED-S in well-trained male cyclists. Twenty-two participants (age: 33.5 ± 6.6 years, height: 181.4 ± 5.2 cm, weight: 76.5 ± 7.4 kg, pe…