Effect of goitrogen administration on the circadian rhythm of serum thyroid stimulating hormone in the rat

1981 ◽  
Vol 98 (3) ◽  
pp. 396-401 ◽  
Author(s):  
B. Stringer ◽  
D. Wynford-Thomas ◽  
B. Jasani ◽  
E. D. Williams
Keyword(s):  
Circadian Rhythm ◽  
Thyroid Hormone ◽  
Circadian Rhythms ◽  
Thyroid Function ◽  
Diurnal Rhythm ◽  
Thyroid Stimulating Hormone ◽  
Male Rats ◽  
Hormone Synthesis ◽  
Serum Tsh

Abstract. Adult male rats were fed a goitrogen, aminotriazole, for 74 days at a dose known to suppress thyroid function completely. At the end of this period, these animals along with matched controls were killed in groups of seven at 3 hourly intervals throughout a 24 hour period, and serum TSH, T3, T4 and albumin assayed. No significant circadian rhythms of T3, T4 or albumin were found in either, but a highly significant rhythm of TSH was demonstrated both in controls and goitrogen treated groups, with a diminished relative amplitude in the latter. The results indicate that a significant diurnal rhythm of serum TSH persists in the rat despite long-term blockade of thyroid hormone synthesis and that the existence of this rhythm is therefore independent of the presence of circulating T3 or T4.

Iodide Metabolism and Effects

2020 ◽  
pp. 25-33
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Dietary Supplement ◽  
Thyroid Function ◽  
Thyroid Stimulating Hormone ◽  
Hormone Synthesis ◽  
Serum Tsh ◽  
Tsh Stimulation ◽  
Sensitive Marker

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.

Evaluation of thyroid function in neonatal and adult rats: The neglected endocrine mode of action

2003 ◽  
Vol 75 (11-12) ◽  
pp. 2055-2068 ◽  
Author(s):  
M. S. Christian ◽  
N. A. Trenton
Keyword(s):  
Metabolic Rate ◽  
Thyroid Function ◽  
Critical Period ◽  
Serum Levels ◽  
Thyroid Stimulating Hormone ◽  
Female Rats ◽  
Male Rats ◽  
Adult Rats ◽  
Male And Female Rats ◽  
Serum Tsh

Although known to regulate growth and development, cellular metabolism, the use of oxygen, and basal metabolic rate, thyroid hormones have been only minimally evaluated in neonatal rodents at critical times of development. Despite some modulation of metabolic rate by other hormones, such as testosterone, growth hormone, and norepinephrine, 3,5,3'-triiodothyronine (T3) and 3,5,3',5'-tetraiodothyronine (T4) are the most important metabolic rate modulators. Endpoints used for thyroid function assessment in neonatal and adult rats include thyroid-stimulating hormone (TSH), T3, and T4 levels and histopathology. In rodents, decreased serum levels of T3 and T4 and increased serum TSH levels, with sustained release of TSH and resultant follicular cell hypertrophy/hyperplasia, are typical hormonal and histopathological findings attributable to compounds altering thyroid function. Hypothyroidism early in the neonatal period can affect reproductive endpoints in both male and female rats, with the critical period of exposure being the first two weeks postnatal. Hypothyroidism has been shown to reduce gonadotrophin levels and delay pubertal spermatogenesis in male rats and to block gonadotropin-induced first ovulation in immature female rats by decreasing FSH and luteinizing hormone (LH) serum concentrations. Inclusion of evaluations of TSH, T3, and T4 assays in multigeneration and developmental neurotoxicity protocols may assist in risk assessments.

Changes in pituitary and thyroid function with increasing age in young male rats.

1979 ◽  
Vol 237 (3) ◽  
pp. E224 ◽  
Author(s):  
F Azizi
Keyword(s):  
Thyroid Function ◽  
Subcutaneous Administration ◽  
Young Male ◽  
Thyroid Stimulating Hormone ◽  
Male Rats ◽  
Progressive Decline ◽  
Basal Serum ◽  
Serum T4 ◽  
Serum Tsh ◽  
Bovine Tsh

As the age of young adult male rats increased from 30 to 150 days, the serum thyroxine (T4) decreased by 50% and the serum thyroid-stimulating hormone (TSH) increased by 250%. There was no change in the serum triiodothyronine (T3). The increment in serum TSH after injection of thyrotropin-releasing hormone (TRH) was not significantly different at any of the ages studied, but the old animals had significantly lower increments in serum T4 and T3 after subcutaneous administration of bovine TSH. Despite a higher basal serum TSH, the older rats had a lesser increase in serum TSH after thyroidectomy or propylthiouracil. Thus, 1) there is a progressive decline in intrinsic thyroid function between 30 and 150 days of age in male rats, and 2) pituitary TSH response to fall in serum concentration of thyroid hormones is also decreased with age.

THE INFLUENCE OF THE PLASMA INORGANIC IODINE CONCENTRATION ON THYROID FUNCTION IN DEHALOGENASE DEFICIENCY

1967 ◽  
Vol 55 (2) ◽  
pp. 361-368 ◽  
Author(s):  
R. McG. Harden ◽  
W. D. Alexander ◽  
S. Papadopoulos ◽  
M. T. Harrison ◽  
S. Macfarlane
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Function ◽  
Iodine Concentration ◽  
Rapid Rise ◽  
Normal Range ◽  
Hormone Synthesis ◽  
Thyroid Hormone Synthesis ◽  
Iodine Metabolism ◽  
Inorganic Iodine ◽  
Circulating Levels

ABSTRACT Iodine metabolism and thyroid function were studied in a patient with hypothyroidism and goitre due to dehalogenase deficiency. Initially the plasma inorganic iodine (PII) level was within the normal range but circulating levels of hormone were low and the thyroid clearance and absolute uptake of iodine (AIU) by the thyroid were high. Administration of iodide supplements resulted in a rapid rise in the plasma thyroxine concentration and restoration of the euthyroid state. Thyroid hormone synthesis appeared to proceed normally when the PII exceeded 1.0 μg/100 ml. This was achieved by increasing the intake of iodide by 612 μg per day. At PII levels around 10 μg/100 ml there was evidence of increased levels of circulating thyroid hormone.

scholarly journals AMIODARON SEBAGAI OBAT ANTI ARITMIA DAN PENGARUHNYA TERHADAP FUNGSI TIROID

2013 ◽  
Vol 3 (2) ◽  
Author(s):  
Starry H. Rampengan
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Thyroid Function ◽  
Hormone Replacement ◽  
Type I ◽  
Peripheral Tissues ◽  
Hormone Synthesis ◽  
Thyroid Hormone Metabolism ◽  
Serum T4 ◽  
Life Threatening

Abstract: Amiodarone is a highly effective anti-arrhythmic agent used in certain arrhythmias from supraventricular tachycardia to life-threatening ventricular tachycardia. Its use is associated with numerous side-effects that could deteriorate a patient’s condition. Consequently, a clinician should consider the risks and benefits of amiodarone before initiating the treatment.The thyroid gland is one of the organs affected by amiodarone. Amiodarone and its metabolite desethyl amiodaron induce alterations in thyroid hormone metabolism in the thyroid gland, peripheral tissues, and probably also in the pituitary gland. These actions result in elevations of serum T4 and rT3 concentrations, transient increases in TSH concentrations, and decreases in T3 concentrations. Both hypothyroidism and hyperthyroidism are prone to occur in patients receiving amiodarone. Amiodarone-induced hypothyroidism (AIH) results from the inability of the thyroid to escape from the Wolff-Chaikoff effect and is readily managed by either discontinuation of amiodarone or thyroid hormone replacement. Amiodarone-induced thyrotoxicosis (AIT) may arise from either iodine-induced excessive thyroid hormone synthesis (type I, usually with underlying thyroid abnormality), or destructive thyroiditis with release of preformed hormones (type II, commonly with apparently normal thyroid glands). Therefore, monitoring of thyroid function should be performed in all amiodarone-treated patients to facilitate early diagnosis and treatment of amiodarone-induced thyroid dysfunction. Key words: Amiodarone, thyroid function, side effect, management, monitoring.     Abstrak: Amiodaron adalah obat antiaritmia yang cukup efektif dalam menangani beberapa keadaaan aritmia mulai dari supraventrikuler takikardia sampai takikardia ventrikuler yang mengancam kehidupan. Namun penggunaan obat ini ternyata menimbulkan efek samping pada organ lain yang dapat menimbulkan perburukan keadaan pasien. Sehingga, dalam penggunaan amiodaron, klinisi juga harus menimbang keuntungan dan kerugian yang ditimbulkan oleh obat ini. Salah satu organ yang dipengaruhi oleh amiodaron adalah kelenjar tiroid. Amiodaron dan metabolitnya desetil amiodaron memengaruhi hormon tiroid pada kelenjar tiroid, jaringan perifer, dan mungkin pada pituitari. Aksi amiodaron ini menyebabkan peningkatan T4, rT3 dan TSH, namun menurunkan kadar T3. Hipotiroidisme dan tirotoksikosis dapat terjadi pada pasien yang diberi amiodaron. Amiodarone-induced hypothyroidism (AIH) terjadi karena ketidakmampuan tiroid melepaskan diri dari efek Wolff Chaikof, dan dapat ditangani dengan pemberian  hormon substitusi T4 atau penghentian amiodaron. Amiodarone-induced thyrotoxicosis (AIT) terjadi karena sintesis hormon tiroid yang berlebihan yang diinduksi oleh iodium (tipe I, biasanya sudah mempunyai kelainan tiroid sebelumnya) atau karena tiroiditis destruktif yang disertai pelepasan hormon tiroid yang telah terbentuk (tipe II, biasanya dengan kelenjar yang normal). Pemantauan fungsi tiroid seharusnya dilakukan pada semua pasien yang diberi amiodaron untuk memfasilitasi diagnosis dan terapi yang dini terjadinya  disfungsi tiroid yang diinduksi amiodaron. Kata Kunci: Amiodaron, fungsi tiroid, efek samping, penanganan, pemantauan.

scholarly journals Thyroid Function Changes and Pubertal Progress in Females: A Longitudinal Study in Iodine-Sufficient Areas of East China

2021 ◽  
Vol 12 ◽  
Author(s):  
Yingying Wang ◽  
Dandan He ◽  
Chaowei Fu ◽  
Xiaolian Dong ◽  
Feng Jiang ◽  
...  
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Thyroid Function ◽  
Pubertal Development ◽  
Thyroid Stimulating Hormone ◽  
East China ◽  
Regression Analyses ◽  
Free Triiodothyronine ◽  
Serum Tsh

BackgroundThe onset of puberty is influenced by thyroid function, and thyroid hormones (THs) fluctuate substantially during the period of pubertal development. However, it needs to be further clarified how THs change at specific puberty stages and how it influences pubertal development in girls. So far, longitudinal data from China are scarce.MethodsA cohort study was conducted among girls during puberty in iodine-sufficient regions of East China between 2017 to 2019. Serum thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were determined for each participant. Thyroid homeostasis structure parameters (THSPs), including the ratio of FT4 to FT3 (FT4/FT3), Jostel’s TSH index (TSHI), and thyroid feedback quantile-based index (TFQI), were calculated. Puberty category scores (PCS), calculated based on the Puberty Development Scale (PDS), was used to assess the stage of puberty. Girls were grouped into three categories according to PCS changes (△PCS) and six categories according puberty stage (BPFP: pre-pubertal at both baseline and follow-up; BPFL: pre-pubertal at baseline and late-pubertal at follow-up, respectively; BPFT: pre-pubertal at baseline and post-pubertal at follow-up, respectively; BLFL: late-pubertal at both baseline and follow-up; BLFT: late-pubertal at baseline and post-pubertal at follow-up, respectively; BTFT: post-pubertal at both baseline and follow-up). Multiple linear regression analyses were used to evaluate the associations of THs changes with pubertal progress.ResultsThe levels of serum TSH and FT3 decreased while serum FT4 increased during the study period (P<0.001). In multiple linear regression analyses, after adjustment for covariables, FT3 decreased by an additional 0.24 pmol/L (95% CI: -0.47 to -0.01) in the higher △PCS group than the lower △PCS group. Compared with the BLFL group, the BPFT group showed an additional decline in FT3 (β= -0.39 pmol/L, 95%CI: -0.73 to -0.04), the BTFT group showed a lower decline in TSH (β=0.50 mU/L, 95% CI: 0.21 to 0.80) and a lower decline in TSHI (β=0.24, 95%CI: 0.06 to 0.41), respectively. There was no association of △FT4 or △TFQI with △PCS or the puberty pattern.ConclusionsSerum TSH and FT3 decreased while serum FT4 increased among girls during puberty. Both the initial stage and the velocity of pubertal development were related to thyroid hormone fluctuations.

scholarly journals Challenges in the functional diagnosis of thyroid nodules before surgery for TSH-producing pituitary adenoma

2021 ◽  
Vol 2021 ◽  
Author(s):  
Keita Tatsushima ◽  
Akira Takeshita ◽  
Shuji Fukata ◽  
Noriaki Fukuhara ◽  
Mitsuo Yamaguchi-Okada ◽  
...  
Keyword(s):  
Pituitary Adenoma ◽  
Thyroid Hormone ◽  
Thyroid Nodule ◽  
Thyroid Nodules ◽  
Thyroid Stimulating Hormone ◽  
Somatostatin Analogue ◽  
Postoperative Phase ◽  
List Type ◽  
Thyroid Scintigraphy ◽  
Serum Tsh

Summary A 50-year-old woman with thyroid-stimulating hormone (TSH)-producing pituitary adenoma (TSHoma) was diagnosed due to symptoms of thyrotoxicosis. Preoperatively, she showed thyrotoxicosis with the syndrome of inappropriate secretion of TSH (SITSH) and had a 5 cm nodule in her thyroid gland. Octreotide was administered preoperatively, which helped lower her serum TSH level but not her thyroid hormone level. These findings were atypical for a patient with TSHoma. The TSHoma was completely resected, and the TSH level dropped below the sensitivity limit shortly after surgery. Interestingly, however, thyroid hormone levels remained high. A clear clue to the aetiology was provided by consecutive thyroid scintigraphy. Although preoperative thyroid scintigraphy did not show a hot nodule and the mass was thought to be a non-functional thyroid nodule, the nodule was found to be hot in the postoperative phase of TSH suppression. By focusing on the atypical postoperative course of the TSHoma, we were able to conclude that this was a case of TSHoma combined with an autonomously functioning thyroid nodule (AFTN). Learning points The diagnosis of autonomously functioning thyroid nodules (AFTNs) depends on suppressed serum TSH levels. If thyroid hormones are resistant to somatostatin analogue therapy or surgery for TSHoma, complications of AFTN as well as destructive thyroiditis need to be considered. It is important to revisit the basics when facing diagnostic difficulties and not to give up on understanding the pathology.

BIOLOGICAL EFFECTS OF 131I AND 125I ISOTOPES OF IODINE IN THE RAT

1976 ◽  
Vol 71 (1) ◽  
pp. 109-114 ◽  
Author(s):  
I. DONIACH ◽  
D. J. SHALE
Keyword(s):  
Thyroid Function ◽  
Biological Effects ◽  
Female Rats ◽  
Long Term Effects ◽  
Significant Elevation ◽  
Radioiodine Uptake ◽  
Male And Female ◽  
Male And Female Rats ◽  
Serum Tsh

SUMMARY From the differences in radiation profiles between 131I and 125I isotopes of iodine it would be expected that they would show different effects on thyroid function. The differences should lead to lower rates of thyroid gland destruction with 125I and hence less post-irradiation hypothyroidism. This difference in biological effect has been demonstrated in rats by indirect assessment of thyroid function. In this report the long-term effects of a range of similar doses of 131I and 125I were compared, in male and female rats, by direct assessment of thyroid function. Seventeen months after receiving 25 and 125 μCi of 131I, male and female rats showed significant elevation of serum TSH concentration and a reduction in 3 h radioiodine uptake. Rats receiving 1 and 5 μCi of 131I and all doses of 125I showed no significant changes in thyroid function. These findings confirm the previously reported differences in effect between the 131I and 125I isotopes of iodine in the rat.

Circadian Rhythms and Homeostatic Mechanisms for Sleep Regulation

2021 ◽  
pp. 65-86
Author(s):  
Cassie J. Hilditch ◽  
Erin E. Flynn-Evans
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Process Model ◽  
Modern Society ◽  
Current Evidence ◽  
Sleep Regulation ◽  
Sleep Homeostasis ◽  
Short And Long Term ◽  
Homeostatic Mechanisms

This chapter examines circadian rhythms and homeostatic mechanisms for sleep regulation. It reviews the current evidence describing the two-process model of sleep regulation and how to assess disruption to either of these sleep drives. This chapter also reviews the role of the photic and non-photic resetting of the circadian rhythm and describes how some aspects of modern society can cause sleep and circadian disruption. Further, this chapter describes how misalignment between the circadian rhythm and sleep homeostasis, such as occurs during jet lag and shift-work, can lead to sleep disruption. The short- and long-term consequences of circadian misalignment are also reviewed.

Subclinical hypothyroidism

2011 ◽  
pp. 543-547
Author(s):  
Jayne A. Franklyn
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Expert Panel ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests ◽  
Serum Tsh

Subclinical hypothyroidism is defined biochemically as the association of a raised serum thyroid-stimulating hormone (TSH) concentration with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The term subclinical hypothyroidism implies that patients should be asymptomatic, although symptoms are difficult to assess, especially in patients in whom thyroid function tests have been checked because of nonspecific complaints such as tiredness. An expert panel has recently classified individuals with subclinical hypothyroidism into two groups (1): (1) those with mildly elevated serum TSH (typically TSH in the range 4.5–10.0 mU/l) and (2) those with more marked TSH elevation (serum TSH >10.0 mU/l).

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