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.

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.

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.

Thyroid Stimulating Hormone Measurement by an Ultrasensitive Assay during Thyroxine Replacement: Comparison with other Tests of Thyroid Function

1987 ◽  
Vol 24 (6) ◽  
pp. 614-619 ◽  
Author(s):  
T Wheatley ◽  
P M S Clark ◽  
J D A Clark ◽  
P R Raggatt ◽  
O M Edwards
Keyword(s):  
Replacement Therapy ◽  
Thyroid Function ◽  
Thyroid Stimulating Hormone ◽  
Biochemical Tests ◽  
Basal Serum ◽  
Total Thyroxine ◽  
Thyroxine Replacement ◽  
Thyroxine Replacement Therapy ◽  
Serum Tsh ◽  
Stimulating Hormone

Serum thyroid stimulating hormone (TSH) was measured using a highly sensitive enzyme-amplified immunoassay in 37 clinically euthyroid patients receiving thyroxine replacement therapy and compared with other biochemical tests of thyroid function. A highly significant correlation ( P<0·001) was found between the basal serum TSH and the increase in serum TSH concentration 20 min after the administration of thyrotropin releasing hormone (TRH). The basal serum TSH was negatively correlated with the serum total thyroxine ( P=0·05). When patients results were classified as abnormal or normal many discrepancies were noted between the various thyroid tests. A suppressed serum TSH was found in 65% of patients with a normal serum total thyroxine. However, in patients on thyroxine replacement therapy a basal TSH measured by enzyme-amplified immunoassay provides the same information as a TRH test.

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&lt;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.

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.

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).

scholarly journals The Effect of Droloxifene and Estrogen on Thyroid Function in Postmenopausal Women1

2000 ◽  
Vol 85 (11) ◽  
pp. 4407-4410
Author(s):  
Ellen Marqusee ◽  
Lewis E. Braverman ◽  
Jennifer E. Lawrence ◽  
Judith S. Carroll ◽  
Ellen W. Seely
Keyword(s):  
Postmenopausal Women ◽  
Treatment Period ◽  
Thyroid Function ◽  
Free T4 ◽  
Double Blind ◽  
Stimulatory Action ◽  
Serum Free ◽  
Serum T4 ◽  
Conjugated Estrogen ◽  
Serum Tsh

Estrogen is known to increase serum T4-binding globulin (TBG) concentrations, thereby increasing serum total T4 concentrations. Serum free T4 concentrations, however, remain normal. Tamoxifen, a selective estrogen receptor modifier (SERM), also raises serum TBG concentrations, but whether newer SERMs with less stimulatory action on the endometrium do so is not known. We, therefore, compared the effect of droloxifene, a SERM, and conjugated equine estrogen on pituitary-thyroid function in normal postmenopausal women. Ten women were treated for 6 weeks with conjugated estrogen (Premarin), 0.625 mg/day, and droloxifene, 60 mg/day, in a double-blind crossover study with an intervening 4-week no-treatment period. We measured serum T4, T3, TBG, free T4 index, and TSH at baseline and at the end of each 6-week period. The baseline values were compared with the 6-week values using paired t tests. The mean (±sd) serum TBG concentrations increased significantly during both treatment periods (baseline, 1.5 ± 0.4 mg/dL; conjugated estrogens, 2.7 ± 0.6 mg/dL; droloxifene, 2.1 ± 0.6 mg/dL; P &lt; 0.001 and P= 0.001, respectively). There were no significant changes in the serum free T4 index. Serum T4 and T3 concentrations increased during both treatment periods, however, the increase was significant only for T4 during the conjugated estrogen treatment period. The serum TSH concentrations increased significantly during both treatment periods (18% during conjugated estrogen and 11% during droloxifene), and the values remained within the normal range in all women. Administration of both conjugated estrogen and droloxifene for 6 weeks increases serum TSH and TBG concentrations, but does not alter free T4 index values in postmenopausal women.

scholarly journals The effect of iodine in patients using povidone-iodine mouth wash on thyroid function

2019 ◽  
Vol 5 (6) ◽  
pp. 1562 ◽  
Author(s):  
Gowri Shankar Murugesan ◽  
Manju Priya Venkat
Keyword(s):  
Thyroid Gland ◽  
Thyroid Function ◽  
Povidone Iodine ◽  
Endocrine System ◽  
Thyroid Stimulating Hormone ◽  
Increased Risk ◽  
Before And After ◽  
Mouth Wash ◽  
Serum Tsh ◽  
Stimulating Hormone

<p class="abstract"><strong>Background:</strong> Thyroid gland is a key part of endocrine system and it performs its functions via two most important thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroid gland is mainly regulated by thyroid-stimulating hormone (TSH). Povidone-iodine (polyvinylpyrrolidone-iodine, PVP-I) mouthwash is commonly used to treat infections of the oral cavity and oropharynx and iodine released from PVP-I can interfere with thyroid function. In this study the effect of brief treatment with povidone-iodine mouth wash on thyroid function was assessed. The aim of the present study was to assess whether iodine is absorbed through oral transmucosal route and interfere with TSH in serum.</p><p class="abstract"><strong>Methods:</strong> Fifty one patients with acute and chronic pharyngitis and tonsillitis were recruited and out of which forty-seven patients were treated with 20 ml of PVP-I mouthwash twice daily for 3 weeks and blood was collected from the respective patients before and after treatment with PVP-I. Serum thyroid stimulating hormone concentration was measured from the collected blood samples of the patients.</p><p class="abstract"><strong>Results:</strong> In the present study there was a small increase in serum TSH concentration during the therapy with PVP-I but the concentration determined was within the normal range.</p><p class="abstract"><strong>Conclusions:</strong> Based on the results of this study we conclude that the use of PVP-I for a brief period transiently increase TSH value and prolonged use should be avoided in people with an increased risk of thyroid dysfunction and other autoimmune disorders.</p>

scholarly journals THE EFFECTS OF KEFIR ON THE INFLAMATORY STATUS AND THYROID FUNCTION (EXPERIMENTAL STUDY ON WISTAR RATS AFTER EXPOSED TO CHLORPYRIFOS)

2016 ◽  
Vol 9 (5) ◽  
pp. 165 ◽  
Author(s):  
Rasipin Rasipin ◽  
Edi Dharmana ◽  
Suharyo Hadisaputro ◽  
Suhartono .
Keyword(s):  
Thyroid Function ◽  
Wistar Rats ◽  
Thyroid Dysfunction ◽  
Corn Oil ◽  
Thyroid Stimulating Hormone ◽  
Male Rats ◽  
Tnf Α ◽  
Male Wistar Rats ◽  
Α Level ◽  
Factor Α

ABSTRACTObjective: Goiter is an enlarged thyroid gland remained a health problem in the agricultural areas. Chlorpyrifos (CPF) is a pesticide widely used byfarmers. Previous studies proved that CPF exposure caused thyroid dysfunction. The objective of this study was to evaluate the effects of kefir on theinflammatory status and thyroid function in male Wistar rats after exposed to CPF using biochemical and histopathological assays.Methods: Male rats were divided into 4 groups, i.e., CPF 5+kefir (5 mg/kg+3.6 ml/200 g, respectively), CPF 5 (5 mg/kg), corn oil (CO 1 ml/200 g), andnegative control (NC: Without CPF, CO, and kefir).Results: Kefir supplementation dose 3.6 ml/200 g once a day for 28 days in the rats after exposed to CPF dose 5 mg/kg once a day for 14 days, inCPF 5+kefir as compared to CPF 5: Significantly (p<0.05) decreased serum tumor necrosis factor-α (TNF-α) level; significantly (p<0.01) maintainedserum levels of tumor growth factor-β (TGF-β) and thyroid stimulating hormone (TSH) not to decrease; not significant (p>0.05) decreased the level ofinterleukin-1β, cluster of differentiation-26 expression and level of T serum; not significant (p>0.05) maintained the level of anti-thyroid peroxidasenot to decrease; and not significant (p>0.05) increased the apoptosis index. This study suggests that CPF exposure causes the inflammatory processwhich leads to thyroid dysfunction.4Conclusion: Kefir supplementation significantly decreased the level of TNF-α and maintained the levels of TGF-β and TSH not to decrease, possible toreduce the inflammatory and thyroid dysfunction processes caused by exposure to CPF in experimental animals.Keywords: Kefir, Chlorpyrifos, Inflammation, Thyroid function. 

scholarly journals Age and Menopausal Status Affect Osteoprotegerin and Osteocalcin Levels in Women Differently, Irrespective of Thyroid Function

2014 ◽  
Vol 7 ◽  
pp. CMED.S15466 ◽  
Author(s):  
Alexander D. Shinkov ◽  
Anna-Maria I. Borissova ◽  
Roussanka D. Kovatcheva ◽  
lliana B. Atanassova ◽  
Jordan D. Vlahov ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Thyroid Function ◽  
Vascular Function ◽  
Thyroid Dysfunction ◽  
Bone Cells ◽  
Menopausal Status ◽  
Thyroid Stimulating Hormone ◽  
Multiple Factors ◽  
Serum Tsh ◽  
Tsh Levels

Osteoprotegerin (OPG) and osteocalcin (OC) are essential bone proteins. Recent studies have demonstrated that they are not secreted solely by bone cells; they play roles in the vascular function and energy metabolism, and they are influenced by multiple factors. The aim of the current study was to investigate the influence of menopause and age on OPG and OC in women with different thyroid-stimulating hormone (TSH) levels. Material and Methods We studied 49 women with elevated TSH, 26 with suppressed TSH, and 67 age-matched euthyroid controls. Of them 64 were menstruating and 78 postmenopausal. Body weight, height, waist circumference (WC), body mass index (BMI), serum TSH, free thyroxin (FT4), OPG, and OC were measured. Results Generally, both OPG and OC were higher in the postmenopausal women than in the menstruating subjects (OPG 3.85 ± 1.49 pmol/L vs. 5.84 ± 2.42 pmol/L, P < 0.001; OC 8.84 ± 3.70 ng/dL vs. 12.87 ± 6.45 ng/dL, P < 0.001), and within the two thyroid dysfunction subgroups and the controls (all P < 0.05). OPG correlated with age (postmenopausal rho = 0.57, P < 0.001; premenopausal rho = 0.31, P = 0.015). Among the premenopausal subjects, OPG was higher in those with low TSH than in the controls ( P = 0.048). OC correlated negatively with BMI and WC in the postmenopausal group (Spearman rho = –-0.25, P = 0.03 and rho = –-0.42, P < 0.001 respectively). OC was higher in the postmenopausal subjects with low TSH than in those with elevated TSH ( P = 0.024), and correlated positively with FT4 (rho = 0.40, P = 0.002) and negatively with TSH (rho = -0.29, P = 0.013). CONCLUSIONS In women, OPG and OC depended differently on age and menopause and, to a lesser extent, on the thyroid function and body composition.

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