Changes in Thyroid Hormones in the Serum and the Thyroid Gland of Hibernating Frogs, Rana temporaria L.

2000 ◽  
Vol 119 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Paweł Kowalczyk ◽  
Jolanta Sotowska-Brochocka
2018 ◽  
Vol 22 (4) ◽  
pp. 40-49 ◽  
Author(s):  
A. R. Volkova ◽  
O. D. Dygun ◽  
B. G. Lukichev ◽  
S. V. Dora ◽  
O. V. Galkina

Disturbance of the thyroid function is often detected in patients with different profiles. A special feature of patients with chronic kidney  disease is the higher incidence of various thyroid function  disturbances, especially hypothyroidism. It is known that in patients  with chronic kidney disease (CKD) iodine excretion from the body is  violated, since normally 90% of iodine is excreted in urine.  Accumulation of high concentrations of inorganic iodine leads to the  formation of the Wolf-Chaikoff effect: suppression of iodine  organization in the thyroid gland and disruption of the thyroid  hormones synthesis. Peripheral metabolism of thyroid hormones is  also disturbed, namely, deiodinase type I activity is suppressed and  peripheral conversion of T4 into T3 is inhibited (so-called low T3  syndrome). Therefore, patients with CKD are often diagnosed with  hypothyroidism, and the origin of hypothyroidism is not always  associated with the outcome of autoimmune thyroiditis. The article  presents an overview of a large number of population studies of  thyroid gland dysfunction in patients with CKD, as well as  experimental data specifying the pathogenetic mechanisms of  thyroid dysfunction in patients with CKD. Therapeutic tactics are still  not regulated. However, in a number of studies, replacement therapy with thyroid hormones in patients with CKD had some advantages.


2021 ◽  
Vol 17 (3) ◽  
pp. 22-26
Author(s):  
I. A. Matsueva ◽  
A. B. Dalmatova ◽  
T. V. Andreychenko ◽  
E. N. Grineva

Treatment of thyrotoxicosis caused by Graves’ disease or multinodular toxic goiter, is not difficult, in most cases, since the prescription of thionamides allows to normalize the level of thyroid hormones quickly and safety. But in a number of cases this therapy might be associated with serious side effects (agranulocytosis, toxic hepatitis, cholestasis), severe allergic reactions and also individual intolerance on thionamides. In such cases lithium carbonate is used, especially in severe thyrotoxic syndrome. It is known, that lithium can accumulate in the thyroid gland at a concentration 3–4 times higher than in the plasma. Perhaps, lithium uses Na+/I- ions. It can inhibit the synthesis and secretion thyroid hormones of thyroid gland. The article presents the cases reported the use of lithium carbonate in thyrotoxicosis treatment before thyroidectomy. Administering low doses of carbonate lithium (900 mg/ per day) renders significant decrease or normalization of thyroid hormones concentration within 7–14 days, thus it let perform thyroidectomy on the patients. No side effects have been identified with such a short course of lithium carbonate treatment.


Author(s):  
Viktoria F Koehler ◽  
Patrick Keller ◽  
Elisa Waldmann ◽  
Nathalie Schwenk ◽  
Carolin Kitzberger ◽  
...  

Introduction Struma ovarii is a teratoma of the ovaries predominantly composed of thyroid tissue. Hyperthyroidism associated with struma ovarii is rare, occurring in approximately 8% of cases. Due to the rarity of struma ovarii, available data are limited to case reports and small case series. Methods and results We report on a 61-year-old female patient with known Hashimoto’s thyroiditis on levothyroxine replacement therapy for years with transition to clinical and biochemical hyperthyroidism despite antithyroid medication with carbimazole (10 mg/day), new diagnosis of urothelial carcinoma and an adnexal mass suspicious of ovarian cancer. The patient underwent resection of the adnexal mass and histopathology revealed a mature teratoma predominantly composed of thyroid tissue showing high levels of sodium iodide symporter protein expression. Following struma ovarii resection and disappearance of autonomous production of thyroid hormones, the patient developed hypothyroidism with severely decreased thyroid hormone levels fT4 and fT3 (fT4 0.4 ng/dL, reference interval 0.9–1.7 and fT3 < 1.0 pg/mL, reference interval 2.0–4.4). This has previously been masked by continued thyroid-stimulating hormone suppression due to long-term hyperthyroidism pre-surgery indicating secondary hypothyroidism, in addition to primary hypothyroidism based on the known co-existing chronic lymphocytic thyroiditis of the orthotopic thyroid gland. Levothyroxine administration was started immediately restoring euthyroidism. Conclusion This case illustrates possible diagnostic pitfalls in a patient with two concurrent causes of abnormal thyroid function. Learning points Struma ovarii is an ovarian tumor containing either entirely or predominantly thyroid tissue and accounts for approximately 5% of all ovarian teratomas. In rare cases, both benign and malignant struma ovarii can secrete thyroid hormones, causing clinical and biochemical features of hyperthyroidism. Biochemical features of patients with struma ovarii and hyperthyroidism are similar to those of patients with primary hyperthyroidism. In such cases, thyroid scintigraphy should reveal low or absent radioiodine uptake in the thyroid gland, but the presence of radioiodine uptake in the pelvis in a whole body radioiodine scintigraphy. We give advice on possible diagnostic pitfalls in a case with two simultaneous causes of abnormal thyroid function due to the co-existence of struma ovarii.


Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1306-1313 ◽  
Author(s):  
Lutz Schomburg ◽  
Cornelia Riese ◽  
Marten Michaelis ◽  
Emine Griebert ◽  
Marc O. Klein ◽  
...  

The thyroid gland is rich in selenium (Se) and expresses a variety of selenoproteins that are involved in antioxidative defense and metabolism of thyroid hormones (TH). Se deficiency impairs regular synthesis of selenoproteins and adequate TH metabolism. We recently generated mice that lack the plasma Se carrier, selenoprotein P (SePP). SePP-knockout mice display decreased serum Se levels and manifest growth defects and neurological abnormalities partly reminiscent of thyroid gland dysfunction or profound hypothyroidism. Thus, we probed the TH axis in developing and adult SePP-knockout mice. Surprisingly, expression of Se-dependent 5′-deiodinase type 1 was only slightly altered in liver, kidney, or thyroid at postnatal d 60, and 5′-deiodinase type 2 activity in brain was normal in SePP-knockout mice. Thyroid gland morphology, thyroid glutathione peroxidase activity, thyroid Se concentration, and serum levels of TSH, T4, or T3 were within normal range. Pituitary TSHβ transcripts and hepatic 5′-deiodinase type 1 mRNA levels were unchanged, indicating regular T3 bioactivity in thyrotropes and hepatocytes. Cerebellar granule cell migration as a sensitive indicator of local T3 action during development was undisturbed. Collectively, these findings demonstrate that low levels of serum Se or SePP in the absence of other challenges do not necessarily interfere with regular functioning of the TH axis. 5′-deiodinase isozymes are preferentially supplied, and Se-dependent enzymes in the thyroid are even less-dependent on serum levels of Se or SePP than in brain. This indicates a top priority of the thyroid gland and its selenoenzymes with respect to the hierarchical Se supply within the organism.


PEDIATRICS ◽  
1966 ◽  
Vol 38 (4) ◽  
pp. 647-651
Author(s):  
Wellington Hung ◽  
Judson G. Randolph ◽  
Domenic Sabatini ◽  
Theodore Winship

Five clinically euthyroid children with lingual or sublingual thyroid glands were seen during a 12-month period. Certain recommendations have been formulated based upon our experience with these patients. A careful physical examination should be performed to demonstrate the presence of a normally located thyroid gland in all children presenting with midline masses in the lingual or sublingual areas. When the thyroid gland cannot be palpated with certainty in these children, a scintiscan with I-131 should be carried out to determine if the mass is an ectopic thyroid gland and if a normally located thyroid gland is present. All children with lingual on sublingual thyroid glands should have a trial of full replacement thyroid hormone therapy before excision is contemplated. Thyroid therapy will prevent further hypertrophy and hyperplasia. Surgical intervention should be reserved for those children in whom there is dysphagia, dysphonia, ulceration, or hemorrhage due to a lingual thyroid gland or if the ectopic thyroid gland fails to decrease in size following a course of treatment with thyroid hormones.


Iodine (I2) is essential in the synthesis of thyroid hormones T4 and T3 and functioning of the thyroid gland. Both T3 and T4 are metabolically active, but T3 is four times more potent than T4. Our body contains 20-30 mg of I2, which is mainly stored in the thyroid gland. Iodine is naturally present in some foods, added to others, and available as a dietary supplement. Serum thyroid stimulating hormone (TSH) level is a sensitive marker of thyroid function. Serum TSH is increased in hypothyroidism as in Hashimoto's thyroiditis. In addition to regulation of thyroid function, TSH promotes thyroid growth. If thyroid hormone synthesis is chronically impaired, TSH stimulation eventually may lead to the development of a goiter. This chapter explores the iodide metabolism and effects of Hashimoto's disease.


Author(s):  
Ildiko Lingvay ◽  
Shelby A. Holt

The thyroid gland, which is the largest endocrine organ, secretes primarily thyroid hormones that play a critical role in the normal growth and development of the maturing human. In the adult, thyroid hormones maintain metabolic stability by regulating oxygen requirements, body weight, and intermediary metabolism. Thyroid function is under hypothalamic-pituitary control, and thus, like the gonads and adrenal cortex, it serves as a classical model of endocrine physiology. In addition, the physiological effects of thyroid hormones are regulated by complex extrathyroidal mechanisms resulting from the peripheral metabolism of the hormones, mechanisms that are not under hypothalamic-pituitary regulation. Thyroid function abnormalities are very prevalent, especially in females and in certain geographic areas, and are often a result of autoimmunity or iodine deficiency. The thyroid originates from two distinct parts of the embryonic endoderm: • The follicular structures arise from a midline thickening of the anterior pharyngeal floor (the base of the tongue), adjacent to the differentiating heart. This thyroid diverticulum first expands ventrally while still attached to the pharyngeal floor by its stalk (thyroglossal duct), and then expands laterally, leading to the characteristic bilobed structure. As the developing heart descends, the thyroid gets pulled into its final position, a process that leads to the rapid stretch and degeneration of the thyroglossal duct. • The parafollicular cells are derived from the ultimobranchial bodies (originating from the neural crest) but ultimately are surrounded by the medial thyroid. The parafollicular cells represents <10 % of the adult thyroid gland. The thyroid completes its structural development by 9 weeks of gestation, the first endocrine organ to assume its definitive form during organogenesis; yet full functional maturation and integration with the hypothalamic-pituitary axis continues throughout gestation. Abnormal thyroid development can lead to persistence of the thyroglossal duct, presence of ectopic thyroid tissue (lingual thyroid, lateral aberrant thyroid), and malposition (thoracic goiter), all of which can remain clinically silent or present later in life as diagnostic challenges. The shape of the human thyroid resembles that of a butterfly.


2000 ◽  
Vol 19 (8) ◽  
pp. 11-26 ◽  
Author(s):  
Denise Kirsten

The thyroid gland contains many follicular cells that store the thyroid hormones within the thyroglobulin molecule until they are needed by the body. The thyroid hormones, often referred to as the major metabolic hormones, affect virtually every cell in the body. Synthesis and secretion of the thyroid hormones depend on the presence of iodine and tyrosine as well as maturation of the hypothalamic-pituitary-thyroid system. Interruption of this development, as occurs with premature delivery, results in inadequate production of thyroid-stimulating hormone and thyroxine, leading to a variety of physiologic conditions. Pathologic conditions occur in the presence of insufficient thyroid production or a defect in the thyroid gland. Laboratory tests are important in diagnosing conditions of the thyroid gland. A thorough history in combination with clinical manifestations and radiologic findings are also useful in diagnosing specific thyroid conditions. Nurses play an important role in identifying and managing thyroid disorders and in providing supportive care to infants and their families.


1996 ◽  
Vol 17 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Anna Capaldo ◽  
Vincenza Laforgia ◽  
Rosaria Sciarrillo ◽  
Antimo Cavagnuolo

AbstractInsulin was administered to Podarcis sicula in winter, when the thyroid gland is inhibited. The activity of the thyroid increased, plasma concentrations of thyroid hormones and hepatic 5'-monodeiodinase activity (MDA) increased, and thyroid stimulating hormone (TSH) concentrations fell to undetectable values. This result confirms the influence of insulin on the activity of the thyroid gland in the lizard species studied. The mechanisms are still unclear, although there is evidence which leads us to believe that insulin is directly responsible for thyroid activation.


1959 ◽  
Vol 18 (1) ◽  
pp. 98-101 ◽  
Author(s):  
CLAIRE J. SHELLABARGER ◽  
JUDITH R. BROWN

SUMMARY 1. A study has been made of the compounds synthesized by and present in the thyroid gland of larval and adult Xenopus laevis using radioactive iodine and chromatography. 2. Tadpoles undergoing active metamorphosis produced thyroxine and trace amounts of 3:5:3′-triiodothyronine. Less thyroxine and no triiodothyronine was detected in tadpoles approaching the end of metamorphosis, and neither compound was detected in tadpoles in early stages of metamorphosis. Adult toads produced thyroxine and trace amounts of triiodothyronine. The presence of monoiodotyrosine and diiodotyrosine was a constant finding. 3. It is suggested that the synthesis of thyroid hormones in amphibia is similar to that in other vertebrates.


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