INFLUENCE OF PROPYLTHIOURACIL AND THYROXINE ON SYNTHESIS AND SECRETION OF THYROID STIMULATING HORMONE IN THE HYPOTHYROID RAT

1964 ◽  
Vol 46 (1) ◽  
pp. 111-123 ◽  
Author(s):  
John L. Bakke ◽  
Nancy Lawrence
Keyword(s):  
Control Level ◽  
Thyroid Stimulating Hormone ◽  
Synthesis Rate ◽  
Initial Size ◽  
Parallel Increase ◽  
Tsh Secretion ◽  
One Year ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Stimulation Of

ABSTRACT Propylthiouracil (PTU) administration to rats produced a progressive and parallel increase in the serum TSH concentration and the thyroid weight over a one year period, but the pituitary TSH content followed a biphasic curve declining markedly for 4 weeks, returning to the control level in 10 weeks and then continuing to rise until a level 5 times the control was achieved after 32 weeks. Either physiologic replacement doses or toxic doses of thyroxine (DL-T4) caused depression of serum TSH levels, significant as early as one hour after administration, followed by an increased pituitary TSH content to as much as 8 times the starting level after 10-60 hours. Thus, T4 did not appear to directly inhibit TSH synthesis during this interval. The reaction appeared to be independent of the duration of prior PTU administration or the initial size and TSH potency of the pituitary gland or the dose of T4 between 2.5 μg/100 g in one day and 40 μg/100 g daily for 4 days. PTU was not essential to this reaction because it also occurred in radiothyroidectomized rats which never received PTU. This rise in pituitary TSH during the period when TSH secretion was suppressed indicated a net pituitary TSH synthesis of as much as 61 mU/h. These values were compatible with those obtained by indirect calculations and consistent with the temporary persistence of the pre-existing TSH synthesis rate although the possibility of the stimulation of TSH synthesis by the T4 was not excluded.

AUGMENTED SECRETION OF TSH IN RESPONSE TO TRH AFTER PRE-TREATMENT WITH DEXAMETHASONE FOR SIX DAYS IN RATS

1976 ◽  
Vol 82 (3) ◽  
pp. 710-714
Author(s):  
Tapio Ranta
Keyword(s):  
Acth Secretion ◽  
Short Term ◽  
Trh Stimulation ◽  
Tsh Secretion ◽  
Pre Treatment ◽  
Dose Levels ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Stimulation Of ◽  
Intact Rats

ABSTRACT Serum TSH and corticosterone concentrations were measured in rats given TRH or exposed to short-term cold, as well as in intact rats, after pretreatment with dexamethasone for six days at two different dose levels (25 and 250 μg/100 g body weight). Both doses increased the secretion of TSH in response to TRH whereas cold-induced TSH secretion was not modified by pre-treatment with dexamethasone. In intact rats serum TSH levels did not differ significantly from controls. In all experiments the steroid blocked ACTH secretion. It was also found that administration of TRH produced a rise in serum corticosterone concentrations. Our results support the view that dexamethasone given for six days facilitates TRH stimulation of the pituitary whilst simultaneously inhibiting the secretion of TRH in response to cold.

scholarly journals Inhibition of pituitary type 2 deiodinase by reverse triiodothyronine does not alter thyroxine-induced inhibition of thyrotropin secretion in hypothyroid rats

2005 ◽  
Vol 153 (3) ◽  
pp. 429-434 ◽  
Author(s):  
P Cettour-Rose ◽  
T J Visser ◽  
A G Burger ◽  
F Rohner-Jeanrenaud
Keyword(s):  
Specific Inhibitor ◽  
Adult Rats ◽  
Reverse T3 ◽  
Brown Adipose ◽  
Tsh Secretion ◽  
Serum T3 ◽  
Serum T4 ◽  
Serum Tsh ◽  
Tsh Levels

Objectives: Intrapituitary triiodothyronine (T3) production plays a pivotal role in the control of TSH secretion. Its production is increased in the presence of decreased serum thyroxine (T4) concentrations and the enzyme responsible, deiodinase type 2 (D2), is highest in hypothyroidism. In order to document the role of this enzyme in adult rats we developed an experimental model that inhibited this enzyme using the specific inhibitor, reverse T3 (rT3). Methods: Hypothyroidism was induced with propylthiouracil (PTU; 0.025 g/l in drinking water) which in addition blocked deiodinase type 1 (D1) activity, responsible for the rapid clearance of rT3 in vivo. During the last 7 days of the experiment, the hypothyroid rats were injected (s.c.) for 4 days with 0.4 or 0.8 nmol T4 per 100 g body weight (bw) per day. For the last 3 days, the same amount of T4 was infused via s.c. minipumps. In additional groups, 25 nmol rT3/100 g bw per day were added to the 3-day infusion of T4. Results: Infusion of 0.4 nmol T4/100 g bw per day did not affect the high serum TSH levels, 0.8 nmol T4/100 g bw per day decreased them to 57% of the hypothyroid values. The infusions of rT3 inhibited D2 activity in all organs where it was measured: the pituitary, brain cortex and brown adipose tissue (BAT). In the pituitary, the activity was 27%, to less than 15% of the activity in hypothyroidism. Despite that, serum TSH levels did not increase, serum T4 concentrations did not change and the changes in serum T3 were minimal. Conclusions: We conclude that in partly hypothyroid rats, a 3-day inhibition of D2 activity, without concomitant change in serum T4 and minimal changes in serum T3 levels, is not able to upregulate TSH secretion and we postulate that this may be a reflection of absent or only minimal changes in circulating T3 concentrations.

Homeopathic Treatment of Subclinical Hypothyroidism—A Series of 19 Cases

Homeopathy ◽  
2021 ◽  
Author(s):  
Luiz Carlos Esteves Grelle ◽  
Luiz Antonio Bastos Camacho
Keyword(s):  
Subclinical Hypothyroidism ◽  
Clinical Importance ◽  
Clinical Problem ◽  
Thyroid Stimulating Hormone ◽  
Exclusion Criteria ◽  
The Mean ◽  
Common Clinical Problem ◽  
Prompt Diagnosis ◽  
Serum Tsh ◽  
Tsh Levels

Abstract Background Subclinical hypothyroidism (SCH) is a common clinical problem. Controversy surrounds the definition, clinical importance, and need for prompt diagnosis and treatment of the mild form of SCH. Aim The aim of the study was to analyze the evolution of serum thyroid stimulating hormone (TSH) levels after a therapeutic homeopathic intervention in women older than 40 years with SCH. Methods This study is a retrospective series of 19 cases of SCH, with serum TSH levels between 5 and 10 mIU/L, treated exclusively with homeopathic medicines prescribed on an individualized basis. Results Nineteen patients were included according to the inclusion and exclusion criteria. Their mean age was 56 years, they were followed for a mean duration of 69 months, the mean number of serum TSH level measurements was 18, and the intervention was successful for 13 patients. Conclusion The homeopathic therapeutic intervention was successful in 68% of the patients, with serum TSH levels back within the normal range (0.5–5.0 mIU/L).

scholarly journals Effects of thyroid hormone and depression on common components of central obesity

2019 ◽  
Vol 47 (7) ◽  
pp. 3040-3049 ◽  
Author(s):  
Fu-Man Du ◽  
Hong-Yu Kuang ◽  
Bin-Hong Duan ◽  
Da-Na Liu ◽  
Xin-Yang Yu
Keyword(s):  
Central Obesity ◽  
Low Density Lipoprotein ◽  
Fasting Blood Glucose ◽  
Density Lipoprotein ◽  
Epidemiological Studies ◽  
Thyroid Stimulating Hormone ◽  
Model Assessment ◽  
Free Triiodothyronine ◽  
Serum Tsh ◽  
Tsh Levels

Objective We investigated the prevalence of abnormal thyroid function and depression in centrally obese participants, and to analyze the relationship of thyroid hormones and depression with components of central obesity. Methods We randomly selected 858 centrally obese participants and 500 non-obese controls in this study. For all participants, we measured serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), body mass index (BMI), waist–hip ratio (WHR), fasting blood glucose and insulin, homeostasis model assessment of insulin resistance (HOMA-IR), lipid concentrations, and blood pressure. Depression was assessed using the Center for Epidemiological Studies-Depression (CES-D) scale. Results Centrally obese participants had a higher prevalence of hypothyroidism and depression than non-obese controls. Serum FT4 levels negatively correlated with BMI and serum TSH levels and positively correlated with BMI, WHR, total triglycerides (TG), total cholesterol (TC), and low density lipoprotein cholesterol (LDL-C). After excluding participants with hypothyroidism and hyperthyroidism, serum FT4 levels showed negative correlation and serum TSH levels showed positive correlation with BMI in the remaining centrally obese participants. CES-D scores positively correlated with BMI. Conclusion We found high prevalences of hypothyroidism and depression among centrally obese participants. FT4 and TSH are important in weight regulation. Depression positively correlated with obesity.

THE INFLUENCE OF METHALLIBURE (ICI 33,828) ON SERUM AND PITUITARY THYROID-STIMULATING HORMONE LEVELS IN THE RAT

1971 ◽  
Vol 49 (4) ◽  
pp. 569-572
Author(s):  
J. R. BOURKE ◽  
S. W. MANLEY ◽  
R. W. HAWKER
Keyword(s):  
Thyroid Stimulating Hormone ◽  
Feedback Mechanism ◽  
Seminal Vesicles ◽  
Endocrine Organs ◽  
System 1 ◽  
Dose Levels ◽  
Higher Doses ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Stimulating Hormone

SUMMARY The effect of methallibure (ICI 33,828), a non-steroidal pituitary inhibitor, on serum and pituitary thyroid-stimulating hormone (TSH) levels has been investigated. A biphasic action of the drug on serum TSH levels was observed, the greatest falls occurring with the lowest doses (2mg/day). Increasing dose and period of administration induced progressive decreases in pituitary TSH content. These results are interpreted in terms of three actions on the thyroid—pituitary system: (1) inhibition of the release of TSH from the pituitary, (2) inhibition of TSH synthesis evident only at higher doses, and (3) a thyroid-blocking action, which is also only observed at the higher dose levels, with consequent pituitary stimulation via the thyroid—pituitary feedback mechanism. Effects upon body weight and weight of endocrine organs are reported, that upon the seminal vesicles being the most marked.

RESPONSE OF NORMAL, HYPOTHYROID AND HYPOTHALAMO-PITUITARY INSUFFICIENT CHILDREN TO SYNTHETIC THYROTROPHIN-RELEASING HORMONE

1971 ◽  
Vol 51 (3) ◽  
pp. 483-488 ◽  
Author(s):  
G. MILHAUD ◽  
P. RIVAILLE ◽  
M. S. MOUKHTAR ◽  
E. BINET ◽  
J. C. JOB
Keyword(s):  
Time Course ◽  
Solid Phase ◽  
Thyroid Stimulating Hormone ◽  
Normal Children ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Tsh Secretion ◽  
Course Changes ◽  
Serum Tsh ◽  
Tsh Deficiency

SUMMARY Thyrotrophin-releasing hormone (TRH) was synthesized by the solid phase technique, administered to 13 children, and the time-course changes in the serum level of thyroid-stimulating hormone (TSH) assessed. In eight normal children, peak levels of TSH occurred 20 min after the injection, and circulating TSH remained significantly raised for 60 min. In three hypothyroid children, the increase in serum TSH was much greater than in normal children, suggesting the existence of large pituitary TSH stores. In two hypopituitary children with TSH deficiency, TSH reserves seemed normal. One of these patients had a craniopharyngioma; after operation, the increase in serum TSH was reduced. These results show that assay of serum TSH after administration of synthetic TRH provides a test which distinguishes pituitary from hypothalamic defects affecting TSH secretion.

Syndrome of'inappropriate secretion of thyroid-stimulating hormone' by partial target organ resistance to thyroid hormones

1981 ◽  
Vol 97 (3) ◽  
pp. 361-368 ◽  
Author(s):  
J. Salmerón De Diego ◽  
C. Alonso Rodriguez ◽  
A. Salazar Orlando ◽  
P. Sanchez Garcia Cervigon ◽  
E. Caviola Mutazzi ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Elevated Serum ◽  
Pituitary Tumour ◽  
Thyroid Stimulating Hormone ◽  
Target Organ ◽  
Resistance To Thyroid Hormones ◽  
Serum Thyroid Hormone ◽  
Serum Tsh ◽  
Tsh Levels ◽  
Stimulating Hormone

Abstract. A 74 year old woman was found to have elevated serum thyroid-stimulating hormone (TSH) levels and elevated serum thyroid hormone levels, with clinical euthyroidism. There was no evidence of a pituitary tumour. TSH levels increased substantially during methimazole therapy. Administration of dexamethasone was followed by a prompt fall in serum TSH levels. Triiodothyronine (T3) was administered over a period of 20 days in doses from 25 μg to as much as 100 μg daily causing a rise in serum T3 above 700 ng/100 ml, a decline of T4 and a blunting of the response to thyrotrophinreleasing hormone (TRH), with normal metabolic responses (pulse rate, photomotogram, cholesterol). These results suggest that the patient's disorder is due to partial target organ resistance to thyroid hormones.

scholarly journals Is it necessary to increase the dose of levothyroxine in patients with hypothyroidism who use omeprazole?

2014 ◽  
Vol 58 (7) ◽  
pp. 731-736 ◽  
Author(s):  
Raquel de Carvalho Abi-Abib ◽  
Mário Vaisman
Keyword(s):  
Treatment Protocol ◽  
Thyroid Stimulating Hormone ◽  
Primary Hypothyroidism ◽  
Sample Median ◽  
Significant Difference ◽  
The Mean ◽  
One Year ◽  
Dose Dependent ◽  
Entire Treatment ◽  
Tsh Levels

Objective It is believed that gastric pH interferes in levothyroxine absorption. Omeprazole, which acts by blocking the secretion of gastric acid, might interfere in hypothyroidism control in patients using levothyroxine and this effect could be dose dependent. The present study aimed to investigate this possibility. Subjects and methods Twenty-one patients with primary hypothyroidism who had been using a stabilized levothyroxine dosage for at least one year were selected and randomly assigned to take omeprazole at the dosage of 40 mg or 20 mg per day. The mean levels of thyroid-stimulating hormone (TSH) before and 3 months after omeprazole usage were compared in the entire sample and in each group. Results Ten patients concluded the entire treatment protocol in the 20 mg group and nine patients in the 40 mg group. There was no significant difference in TSH levels before and 3 months after omeprazole treatment in the entire patient sample (median levels: 2.28 vs. 2.30 mU/L, respectively: p = 0.56). Analysis of each subgroup (20 and 40 mg) showed no significant variation in TSH levels before and 3 months after omeprazole treatment (median levels: 2.24 vs. 2.42 mU/L, p = 0.62, and 2.28 vs. 2.30 mU/L, p = 0.82, respectively). No significant difference in the absolute (p = 0.93) or relative (p = 0.87) delta were observed between the two subgroups. Conclusion Omeprazole in the dosage of 20 or 40 mg/day does not interfere in a clinically relevant manner in the treatment of patients with hypothyroidism that was previously under control.

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.

Does serum TSH level act as a surrogate marker for psychological stress and cardio-metabolic risk among adolescent and young people?

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Niranjan Gopal ◽  
Akash Shivaji Pune ◽  
Roshan Takhelmayum ◽  
Ashok Kumar Ahirwar
Keyword(s):  
Blood Pressure ◽  
Metabolic Syndrome ◽  
Psychological Stress ◽  
Surrogate Marker ◽  
Thyroid Stimulating Hormone ◽  
First Year ◽  
Metabolic Risk ◽  
Anthropometric Measures ◽  
Serum Tsh ◽  
Tsh Levels

Abstract Objectives The incidence of metabolic syndrome is increasing even at younger ages. Metabolic syndrome constitutes a group of cardiovascular risk factors that include high cholesterol, triacylglycerol, hyperglycemia, central obesity, etc., which increases the risk of cardiovascular disease, diabetes mellitus, may be even cancer. Indian students enter colleges just after crossing their adolescent age and will be exposed to greater academic stress. Psychological stress or depression is associated with transient change in thyroid hormones level or dysfunction. To explore an association among serum Thyroid Stimulating Hormone (TSH) levels, fT3:fT4 ratio, psychological stress scores, and selected known cardio-metabolic risk markers. Methods Forty first year MBBS students were included. Their demographic, anthropometric variables, and the blood pressure were documented. Serum TSH, fT3, fT4, and salivary cortisol level was quantified. The stress level was assessed using Cohen Perceived Stress Scale Scoring. Data were expressed in mean ± standard deviation. Data (parametric/non-parametric) were compared by Independent unpaired ANOVA or Kruskal Wallis test whichever is appropriate. Spearmen correlation analysis was performed. Results Serum TSH and Cohen stress score are negatively correlated (r=−0.152), but serum cortisol showed (r=0.763) a positive correlation. TSH levels and the marks obtained in the summative assessments were negatively correlated and the correlation was not statistically significant. Conclusions The psychological stress is associated with low serum TSH, high cortisol, and poor academic performance in first year MBBS students. Blood pressure, plasma glucose, and anthropometric measures were not associated with the psychological stress.

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