Effect of neonatal hyperthyroidism upon the regulation of TSH secretion in rats

1984 ◽  
Vol 105 (1) ◽  
pp. 31-39 ◽  
Author(s):  
M. E. Besa ◽  
A. M. Pascual-Leone
Keyword(s):  
Saline Control ◽  
Hypothalamic Lesions ◽  
Tsh Secretion ◽  
Tsh Regulation ◽  
Neonatal Hyperthyroidism ◽  
And Control ◽  
Two Populations ◽  
Tsh Levels

Abstract. The neo-T4 syndrome was induced in rats by administration of 30 μg T4/in 5 doses starting on the first day of life. In the first experiment (A), neo-T4 and saline-control rats were divided into two populations, one of which was thyroidectomized on day 25. All rats then received 5 μg T4/100 g b.w. on days 42, 43 and 44, and were sacrificed on day 45. In the second experiment (B), neo-T4 and saline-control rats were thyroidectomized at 25 days of age and were sacrificed 10, 20 and 40 days after the operation. In both experiments, pituitary and plasma TSH and pituitary GH were determined. T4 administration has the same effect on plasma and pituitary TSH regulation in neo-T4 and control rats, thyroidectomized or not. The increase in pituitary GH produced by T4 is smaller in the thyroidectomized neoT4 animals. The comparison between T4-induced increases of pituitary TSH in thyroidectomized neo-T4 and saline control-rats, and the corresponding decreases in non-thyroidectomized animals suggests an alteration in TSH synthesis which has previously been compared with that found in rats with lesions of the hypothalamus. However, the changes in pituitary and plasma TSH levels in neo-T4 rats at different intervals after thyroidectomy do not coincide with those described for rats with hypothalamic lesions. The possible perturbation in pituitary TSH synthesis proposed for neo-T4 rats accords with the lack of response to TRH found in adult animals treated with thyroxine, an effect which remains even when plasma T4 levels decrease.

Increased pituitary thyroxine 5′-deiodinase activity in adult rats rendered hyper- or hypo-thyroid during perinatal life

1985 ◽  
Vol 63 (4) ◽  
pp. 279-282 ◽  
Author(s):  
Peter Walker
Keyword(s):  
Adult Rats ◽  
Feedback Effects ◽  
Adult Rat ◽  
Gland Weight ◽  
Deiodinase Activity ◽  
Body Weights ◽  
Tsh Secretion ◽  
Neonatal Hyperthyroidism ◽  
Perinatal Hypothyroidism ◽  
And Control

Perinatal thyroid dysfunction in the rat leads to permanent alterations in pituitary TSH secretion in the adult animal. Thus, neonatal hyperthyroidism (NH) and perinatal hypothyroidism (PH) both result in apparent increased pituitary sensitivity to the feedback effects of thyroid hormones in the adult rat. To determine if increased intrapituitary generation of triiodothyronine (T3) might account for these observations, we measured thyroxine (T4) 5′-deiodinase activity in pituitary homogenates of adult NH and PH rats. NH was induced by injecting neonatal rats with 12 daily sc injections of T4 (0.4 μg/g body weight (BW)). Control rats received vehicle alone. PH was induced by administering 0.05% 6-n-propylthiouracil in the drinking water to pregnant dams from the 16th day of gestation through the 12th day postpartum. Thereafter, a normal water supply was substituted. NH and PH rats were allowed to mature and were sacrificed at 105 days of age. Serum T4, T3, and TSH concentrations were measured by radioimmunoassay. Pituitary T4 5′-deiodinase activity was assessed by the measurement of T3 formation by pituitary homogenates incubated in the presence of 0.65 μM T4 and 100 mM dithiothreitol at 37 °C for 90 min. Body weights of adult NH and PH rats were slightly but not significantly decreased compared with control rats. Relative pituitary gland weight (milligrams per 100 g BW) was significantly decreased in adult PH rats (P < 0.005) but not in adult NH rats. In adult NH rats, serum T4 and T3 concentrations were significantly decreased (P < 0.01) compared with control rats. Serum TSH concentrations were similar. No significant differences in serum T4, T3, and TSH concentrations were noted between adult PH and control rats. Pituitary T4 5′-deiodinase activity was significantly increased in both adult NH and PH rats compared with controls (NH > PH > control; P < 0.005, and P < 0.05, respectively). These data indicate that pituitary T4 5′-deiodinase activity is significantly increased in adult NH and PH rats. Increased pituitary T4 5′-monodeiodination may explain, in part, the apparent increased thyrotroph sensitivity to feedback effects of thyroid hormone in these animals.

Thyroid Functions in Children on Levetiracetam or Valproic Acid Therapy

2020 ◽  
Author(s):  
Elif Karatoprak ◽  
Samet Paksoy
Keyword(s):  
Valproic Acid ◽  
Subclinical Hypothyroidism ◽  
Control Group ◽  
Thyroid Function Tests ◽  
Healthy Children ◽  
Control Groups ◽  
Acid Therapy ◽  
Significant Difference ◽  
And Control ◽  
Tsh Levels

AbstractThe aim of this study was to investigate the thyroid functions in children receiving levetiracetam or valproate monotherapy. We retrospectively reviewed the records of children with controlled epilepsy receiving valproic acid (VPA group) or levetiracetam monotherapy (LEV group) for at least 6 months. Free thyroxine 4 levels (fT4) and thyroid stimulating hormone (TSH) levels were compared between VPA group, LEV group, and age- and gender-matched healthy children (control group). A total of 190 children were included in the study: 63 were in the VPA, 60 in the LEV, and 67 in the control group. Although there was no significant difference regarding average fT4 levels, higher TSH levels were found in the VPA group when compared with the LEV and control groups (p < 0.001 and p < 0.001, respectively). There was no significant difference in terms of fT4 and TSH values in the LEV group when compared with the control group (p = 0.56 and p = 0.61, respectively). Subclinical hypothyroidism (defined as a TSH level above 5 uIU/mL with a normal fT4 level was detected in 16% of patients in the VPA group, none in the LEV and control groups. Our study found that VPA therapy is associated with an increased risk of subclinical hypothyroidism while LEV had no effect on thyroid function tests.

The impact of maternal protein restriction during perinatal life on the response to a septic insult in adult rats

2020 ◽  
pp. 1-8
Author(s):  
Reza Khazaee ◽  
Anastasiya Vinokurtseva ◽  
Lynda A. McCaig ◽  
Cory Yamashita ◽  
Daniel B. Hardy ◽  
...  
Keyword(s):  
Control Diet ◽  
Protein Restriction ◽  
Saline Control ◽  
Female Adult ◽  
Adult Rats ◽  
Male And Female ◽  
Maternal Protein Restriction ◽  
And Control ◽  
The Impact ◽  
Septic Insult

Abstract Although abundant evidence exists that adverse events during pregnancy lead to chronic conditions, there is limited information on the impact of acute insults such as sepsis. This study tested the hypothesis that impaired fetal development leads to altered organ responses to a septic insult in both male and female adult offspring. Fetal growth restricted (FGR) rats were generated using a maternal protein-restricted diet. Male and female FGR and control diet rats were housed until 150–160 d of age when they were exposed either a saline (control) or a fecal slurry intraperitoneal (Sepsis) injection. After 6 h, livers and lungs were analyzed for inflammation and, additionally, the amounts and function of pulmonary surfactant were measured. The results showed increases in the steady-state mRNA levels of inflammatory cytokines in the liver in response to the septic insult in both males and females; these responses were not different between FGR and control diet groups. In the lungs, cytokines were not detectable in any of the experimental groups. A significant decrease in the relative amount of surfactant was observed in male FGR offspring, but this was not observed in control males or in female animals. Overall, it is concluded that FGR induced by maternal protein restriction does not impact liver and lung inflammatory response to sepsis in either male or female adult rats. An altered septic response in male FGR offspring with respect to surfactant may imply a contribution to lung dysfunction.

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.

Cardiovascular parameters in a mixed-sex swine study of severe decompression sickness treated with the emulsified perfluorocarbon Oxycyte

2015 ◽  
Vol 118 (1) ◽  
pp. 71-79 ◽  
Author(s):  
R. T. Mahon ◽  
W. A. Cronin ◽  
M. Bodo ◽  
S. Tirumala ◽  
D. P. Regis ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Decompression Sickness ◽  
Mortality Rates ◽  
Rapid Onset ◽  
Systemic Arterial Pressure ◽  
Saline Control ◽  
Physiological Effects ◽  
Control Groups ◽  
And Control ◽  
Observation Period

Intravenous perfluorocarbons (PFC) have reduced the effects of decompression sickness (DCS) and improved mortality rates in animal models. However, concerns for the physiological effects of DCS combined with PFC therapy have not been examined in a balanced mixed-sex population. Thirty-two (16 male, 16 female) instrumented and sedated juvenile Yorkshire swine were exposed to 200 feet of seawater (fsw) for 31 min of hyperbaric air. Pulmonary artery pressure (PAP), cardiac output (CO), and systemic arterial pressure (SAP) were monitored before (control) and after exposure. Animals were randomized to treatment with Oxycyte (5 ml/kg; Oxygen Biotherapeutics, Inc., Morrisville, NC) vs. saline (control) with 100% oxygen administered upon DCS onset; animals were observed for 90 min. Parameters recorded and analyzed included PAP, CO, and SAP. In all animals PAP began to rise prior to cutis marmorata (CM) onset, the first sign of clinical DCS, generally peaking after CM onset. Female swine, compared with castrated males, had a more rapid onset of CM (7.30 vs. 11.46 min postsurfacing) and earlier onset to maximal PAP (6.41 vs. 9.69 min post-CM onset). Oxycyte therapy was associated with a sustained PAP elevation above controls in both sexes (33.41 vs. 25.78 mmHg). Significant pattern differences in PAP, CO, and SAP were noted between sexes and between therapeutic groups. There were no statistically significant differences in survival or paralysis between the PFC and control groups during the 48-h observation period. In conclusion, Oxycyte therapy for DCS is associated with a prolonged PAP increase in swine. These species and sex differences warrant further exploration.

scholarly journals HbA1c levels in individuals heterozygous for hemoglobin variants

2017 ◽  
Vol 63 (4) ◽  
pp. 341-346
Author(s):  
Ricardo Silva Tavares ◽  
Fábio Oliveira de Souza ◽  
Isabel Cristina Carvalho Medeiros Francescantonio ◽  
Weslley Carvalho Soares ◽  
Mauro Meira Mesquita
Keyword(s):  
Test Group ◽  
Exchange Chromatography ◽  
Group Method ◽  
Control Group ◽  
Significant Difference ◽  
Hemoglobin Variants ◽  
Different Populations ◽  
And Control ◽  
Two Populations ◽  
Hba1c Levels

Summary Objective: To evaluate the levels of glycated hemoglobin (HbA1c) in patients heterozygous for hemoglobin variants and compare the results of this test with those of a control group. Method: This was an experimental study based on the comparison of HbA1c tests in two different populations, with a test group represented by individuals heterozygous for hemoglobin variants (AS and AC) and a control group consisting of people with electrophoretic profile AA. The two populations were required to meet the following inclusion criteria: Normal levels of fasting glucose, hemoglobin, urea and triglycerides, bilirubin > 20 mg/dL and non-use of acetylsalicylic acid. 50 heterozygous subjects and 50 controls were evaluated between August 2013 and May 2014. The comparison of HbA1c levels between heterozygous individuals and control subjects was performed based on standard deviation, mean and G-Test. Results: The study assessed a test group and a control group, both with 39 adults and 11 children. The mean among heterozygous adults for HbA1c was 5.0%, while the control group showed a rate of 5.74%. Heterozygous children presented mean HbA1c at 5.11%, while the controls were at 5.78%. G-Test yielded p=0.93 for children and p=0.89 for adults. Conclusion: Our study evaluated HbA1c using ion exchange chromatography resins, and the patients heterozygous for hemoglobin variants showed no significant difference from the control group.

Method of Generated Responses and Schizophrenic Deficit

1971 ◽  
Vol 29 (3) ◽  
pp. 975-982
Author(s):  
Anne Marie Bercik ◽  
John H. Mueller
Keyword(s):  
Paired Associates ◽  
High Dominance ◽  
The Difference ◽  
And Control ◽  
Two Populations ◽  
Do So

Schizophrenic and control Ss were compared on the method of generated responses (MGR) and conventional paired-associates (PA), using lists of stimuli which elicited either primarily one response or several responses. The low-dominance list was more difficult, and schizophrenics were generally slower in learning. The MGR, with Ss producing their own responses, was easier than conventional PA (yoked controls). While the MGR reduced the difference between the low- and high-dominance lists, it did not do so differentially for the two populations. The results were discussed in terms of Broen and Storms' theory of “collapsed” response hierarchies in schizophrenia.

Texture Analysis and Genetic Algorithms for Osteoporosis Diagnosis

2019 ◽  
Vol 34 (05) ◽  
pp. 2057002
Author(s):  
Laatra Yousfi ◽  
Lotfi Houam ◽  
Abdelhani Boukrouche ◽  
Eric Lespessailles ◽  
Frédéric Ros ◽  
...  
Keyword(s):  
Genetic Algorithms ◽  
Texture Analysis ◽  
Image Features ◽  
Diagnosis Of Osteoporosis ◽  
Occurrence Matrix ◽  
Two Parameters ◽  
And Control ◽  
Parameter Dependent ◽  
Two Populations ◽  
Distance Parameter

Early diagnosis of osteoporosis can efficiently predict fracture risk. There is a great demand to prevent this disease. The goal of this study was to distinguish osteoporotic cases from healthy controls on 2D bone radiograph images, using texture analysis and genetic algorithms (GAs). Gray Level Co-occurrence Matrix (GLCM), Run length Matrix (RLM) and Binarized Statistical Image Features (BSIF) were used for texture analysis. Features are numerous and parameter-dependent. The related experts can pick out the useful input features for the classifier. It however remains a difficult task and may be inefficient or even harmful as the data pattern is not clear. In this paper, GAs were used to optimize the two parameters of the co-occurrence matrix (distance parameter or pixel separation, orientation or direction) and the number of gray levels used in the preprocessing quantification step. GAs were also used to select the best combination of features extracted from GLCM and RLM matrices. Experiments were conducted on two populations composed of Osteoporotic Patients and Control Subjects. Results show that GAs combined with GLCM and BSIF features can improve the classification rates (ACC = 87.50%) obtained using GLCM (ACC = 77.8%) alone.

scholarly journals Thoracic periaortic adipose tissue is increased in patients with subclinical hypothyroidism

2015 ◽  
Vol 172 (5) ◽  
pp. 553-559
Author(s):  
Ömer Akyürek ◽  
Duran Efe ◽  
Zeynettin Kaya
Keyword(s):  
Adipose Tissue ◽  
Subclinical Hypothyroidism ◽  
Smoking Status ◽  
Control Group ◽  
Laboratory Findings ◽  
Significant Difference ◽  
Sh Group ◽  
The Difference ◽  
And Control ◽  
Tsh Levels

ObjectiveTo evaluate thoracic periaortic adipose tissue (TAT) volume in patients with subclinical hypothyroidism (SH) in comparison with controls and in relation to cardiovascular risk factors.MethodsThe study population consisted of 28 newly diagnosed SH patients (mean (s.d.) age: 37.3 (±11.4) years, 85.7% were females) and 37 healthy volunteers (mean (s.d.) age: 35.3 (±10.7) years, 81.5% were females). Comparisons between patient and control groups used demographic characteristics, anthropometrics, and laboratory findings. All participants underwent thoracic radiographic assessment in the supine position, using an eight-slice multidetector computed tomography scanner and TAT volume was measured.ResultsThe TAT volume was determined to be 27.2 (±12.7) cm3 in the SH group and 16.3 (±8.1) cm3 in the control group, and the difference was statistically significant (P<0.001). In addition, TSH levels were significantly higher in the patient group compared with the control group (P<0.001). A significant correlation was also found between TSH levels and TAT volume (r=0.572; P<0.001). In SH patients, no significant difference was noted in TAT levels with respect to sex (P=0.383) or concomitant smoking status (P=0.426).ConclusionsOur findings indicate that SH patients have significantly higher TAT values than controls and that increased TAT levels correlate with increased TSH levels.

β-Neoendorphin inhibits thyrotrophin secretion in rats

1983 ◽  
Vol 104 (4) ◽  
pp. 437-442 ◽  
Author(s):  
Terunori Mitsuma ◽  
Tsuyoshi Nogimori
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Thyrotrophin Releasing Hormone ◽  
Specific Radioimmunoassay ◽  
Tsh Secretion ◽  
Pretreated Group ◽  
The Central Nervous System ◽  
Tsh Levels

Abstract. The effects of β-neoendorphin on thyrotrophin-releasing hormone (TRH) and thyrotrophin (TSH) secretion in rats were studied. β-neoendorphin (500 μg/kg) was injected iv, and the rats were decapitated serially. TRH, TSH, thyroxine (T4) and 3,3',5-triiodothyronine (T3) were measured by means of a specific radioimmunoassay for each. Hypothalamic immunoreactive TRH (ir-TRH) content increased significantly after β-neoendorphin injection, and plasma concentrations tended to decrease, but not significantly so. Plasma TSH levels decreased significantly in a dose-related manner with a nadir at 40 min. Plasma T4 and T3 levels did not change after the injection. Plasma ir-TRH and TSH responses to cold were significantly inhibited by β-neoendorphin, but the plasma TSH response to TRH was not. Naloxone partially prevented the inhibitory effect of β-neoendorphin on TSH release. In the haloperidol- or 5-hydroxytryptophan-pretreated group, the inhibitory effect of β-neoendorphin on TSH release was prevented, but not in the l-dopa- or para-chlorophenylalanine-pretreated group. These drugs alone did not affect plasma TSH levels at the dose used. These findings suggest that β-neoendorphin acts on the hypothalamus by inhibiting TRH release, which may be modified by amines of the central nervous system.

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