Basal Thyroid-stimulating Hormone Levels Research Articles

Thyroid-stimulating hormone levels are associated with estradiol levels and impact reproductive outcomes in preconceptionally euthyroid women undergoing their first IVF/ICSI cycles.

Controlled ovarian hyperstimulation (COH) has been reported to affect thyroid function; however, the impact of thyroid-stimulating hormone (TSH) levels during COH on embryo development and early reproductive outcomes has largely not been determined. Therefore, the aim of the present study was to investigate whether TSH levels are associated with COH and impact early reproductive outcomes in preconceptionally euthyroid women. This was a prospective cohort study. A total of 338 euthyroid women who underwent their first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment using the gonadotropin releasing hormone agonist (GnRH-a) protocol were included. Samples were collected at different representative time points for TSH and estradiol measurements. TSH levels significantly increased with the administration of Gn and maintained this tendency until the trigger day. Basal TSH levels increased along with basal estradiol levels and remained stable when estradiol levels were higher than 150 pmol/L. On the trigger day, TSH levels changed with increasing estradiol levels in the high-normal basal TSH group but not in the low TSH group. TSH did not impact clinical pregnancy or early pregnancy loss after adjusting for age, stage or number of embryos. Serum TSH levels change significantly during COH and are associated with significant changes in estradiol levels. However, euthyroid women with high-normal TSH levels showed similar development potential for inseminated embryos and early reproductive outcomes compared to those with low TSH levels.

P-133 A study of the relationship between in vitro embryo development and maternal hypothyroidism

Abstract Study question Are there an association between the maternal thyroid condition and in vitro fertilization (IVF) outcomes? Summary answer Maternal hypothyroidism was found to be related to oocyte maturation and blastocyst development. What is known already Previous studies have shown that thyroid-stimulating hormone (TSH) levels affect ovarian stimulation in assisted reproductive technology (ART). In addition, changes in serum TSH levels have been linked to a sub-optimal environment for the implantation and development of the embryo. Thyroid-related receptors are present in granulosa cells, ovaries, and the endometrium. In addition, those receptors play a role in ovulation and folliculogenesis. This study aims to determine the association between maternal hypothyroidism and adverse implications for IVF outcomes in IVF/ICSI treated women. Study design, size, duration This retrospective study performed 333 cycles of 208 patients with TSH levels ranging from 0.043-16.627 µIU/mL, treated at the RMC National IVF Center between 2019 and 2022. The study population consisted of 1171 oocytes, which were divided into two groups based on their maternal basal TSH levels: normal TSH ≤ 2.5 µIU/mL (control group, n = 865, euthyroid) and higher TSH > 2.5 µIU/mL (case group, n = 306, hypothyroid). Participants/materials, setting, methods Maternal basal serum TSH levels were measured using Fluorescence Enzyme Immunoassay on the third day of the menstrual cycle. IVF outcome expressed oocyte maturation, fertilization, cleavage, and blastocyst formation rate. Oocytes were divided into mature (metaphase II) and immature (metaphase I and prophase I) groups. Blastocysts are graded by the Kato Ladies Clinic classification system and divided into high potential (A and B grades) and low potential (C, D, and E grades) groups. Main results and the role of chance In our study, there was no statistically significant difference in age and partner’s semen criteria between the two groups (p > 0.05). As regards oocyte maturation, MII oocytes retrieved significantly higher in the control group (82.2% vs. 75.8%). Logistic regression analysis found that TSH levels > 2.5 µIU/mL were related to statistically significantly increased risks of oocyte maturation stages like MI or GV (Age affect adjusted model: B = 0.456, p = 0.005; OR = 1.578, 95% CI = 1.146-2.175). The fertilization, cleavage, and blast formation rates have no differences between the groups. However, 91% (n = 324/356) of higher potential blastocysts in the control group were significantly higher than the case group (79.7%, n = 106/133). While, by the logistic regression analysis found that higher TSH levels ( > 2.5 µIU/mL) were related to statistically significantly increased risks of lower potential for implantation grades (B = 0.947, p = 0.001; OR = 2.579, 95%CI = 1.477-4.502). Limitations, reasons for caution The study relied on TSH as the primary indicator of thyroid function and excluded participants with abnormal prolactin levels. Other markers, such as FT4 and TSHR, should also be considered for a thorough evaluation of thyroid function. Wider implications of the findings Thyroid dysfunction can negatively impact IVF success, and screening and managing thyroid function in women undergoing IVF are essential. More research is needed to understand the mechanisms and develop strategies to improve oocyte and blastocyst quality. Trial registration number not applicable

Long-Term Effects of Lithium Use on Children and Adolescents: A Retrospective Study from Turkey.

Background: The aim of this study was to evaluate the long-term effects of lithium treatment on white blood cell (WBC) count, serum creatinine, and thyroid-stimulating hormone (TSH) levels in children and adolescents with bipolar disorder (BD) and non-BD in a Turkish children and adolescent sample. Methods: The study is based on retrospective chart review. Children and adolescent patients with BD and non-BD prescribed lithium in a mental health and neurological disorders hospital between 2012 and 2017 were included in the study. Data were collected from the electronic medical files. Laboratory values for WBC count, serum creatinine, and TSH levels at baseline within the week before the onset of lithium, and at 1st, 3rd, 6th, and 12th month of treatment were recorded. Results: A total of 143 patients (82 females, 61 males; 100 BD, 43 non-BD) aged 9-18 were included. Non-BD diagnoses were psychotic and schizoaffective disorders, unipolar depression, attention-deficit/hyperactivity disorder, conduct disorder, severe mood dysregulation syndrome, borderline personality disorder, and autism. Mean age of the participants were 15.90 ± 1.16 years for the bipolar group and 14.88 ± 1.79 years for the nonbipolar group. Patients with BD reported more adverse effects. There was a statistically significant increase in WBC counts and TSH levels at any time point. A statistically significant elevation in serum creatinine was found at 3rd and 12th month of treatment. During the course of lithium treatment, WBC counts exceeded 13,000 in 14 (9.8%) patients, and TSH levels exceeded 5.5 mU/L in 41 patients (28.6%). Twenty-one (14.68%) patients were started on thyroxin replacement. Basal TSH levels and duration of the lithium treatment were higher in the participants with TSH levels exceeding 5.5 mU/L. Lithium maximum dose, lithium blood level, basal TSH level, and duration of treatment were higher in the participants receiving thyroxin replacement. No patients had serum creatinine levels exceeding the normal reference values. Conclusion: Our study suggests that lithium is a generally safe and tolerable agent for children and adolescents with BD and non-BD; however, close monitoring of thyroid functions particularly in patients with a higher basal TSH level and longer duration of lithium use is important.

Effects of controlled ovarian stimulation on thyroid stimulating hormone in infertile women

ObjectiveTo study the effects of long-acting gonadotropin-releasing hormone agonist (GnRH-a) on thyroid function in euthyroid patients of in vitro fertilization (IVF)/ intracytoplasmic sperm injection of embryo transfer (ICSI-ET) and to investigate the timing and alteration of thyroid stimulating hormone (TSH) during controlled ovarian stimulation(COS). Materials and methodsEuthyroid patients scheduled for IVF/ICSI were enrolled. Euthyroidism was defined as having no history of hypothyroidism with normal TSH before IVF. Long GnRH-a protocol was chosen as COS protocol. 207 patients were divided into two groups based on basal serum TSH level: group A with 0.35mIU/L＜TSH＜2.5mIU/L (n = 137) and group B with 2.5mIU/L ≤ TSH＜4.5mIU/L (n = 70). Serum TSH was tested on 6 time points: before COS (2–5days in menstrual cycle, before GnRH-a injection), Gn injection day 1, Gn injection day 5, human chorionic gonadotropin (HCG) day, 14 and 28 days after transplantation. The serum TSH, clinical pregnancy and abortion rate were investigated. ResultThe serum TSH value was significantly (P < 0.05) increased after injection of long-acting GnRH-a in all patients. Both groups had significant (P < 0.05) increases in serum TSH level after long-acting GnRH-a injection. The TSH level was increased in 131(63.3%) patients after GnRH-a injection, of which twenty (9.7%) had subclinical hypothyroidism with TSH level over 4.5 mIU/L. The other 76 (36.7%) patients had decreased TSH. In group A, 79 (57.7%) patients showed an increase of TSH, including three patients (2.2%) with simultaneous rise of TPOAb and four (2.9%) diagnosed of subclinical hypothyroidism with TSH level over 4.5 mIU/L, and the rest fifty-eight (42.3%) patients had decreased TSH with one patient with elevated TPOAb who was diagnosed with subclinical hyperthyroidism. In group B, fifty-two (74.3%) patients showed an increase of TSH, including thirteen (18.6%) patients with elevated TPOAb and sixteen (22.9%) patients diagnosed of subclinical hypothyroidism with TSH level over 4.5 mIU/L, and the rest eighteen (25.7%) patients had decreased TSH with one patient diagnosed with subclinical hyperthyroidism. Group B had a significant higher proportion of patients with elevated serum TSH than group A (P ＜ 0.05). Compared to the baseline level, serum TSH ascended distinctly and reached peak level on HCG day in all patients. Group A and B had similar trends of alteration. Patients in group A had significantly (P＜0.05) higher clinical pregnancy rate than in group B. No significant (P＞0.05) difference in abortion rate were observed between the two groups. ConclusionGnRH-a can significantly increase serum TSH levels with possible development of subclinical thyroid dysfunction. Infertile patients with serum TSH > 2.5 mIU/L are more susceptible to GnRH-a while patients with basal TSH less than 2.5 mIU/L may get a higher clinical pregnancy rate when receiving IVF/ICSI.

Outcome of in vitro fertilization in women with subclinical hypothyroidism

BackgroundPrevious studies examining associations between subclinical hypothyroidism (SCH) with in vitro fertilization (IVF) outcome indicate some benefits of levothyroxine (LT4) treatment. But IVF outcomes in treated SCH women whose serum Thyroid Stimulating Hormone (TSH) concentration did and did not exceed 2.5 mIU/L before the IVF cycle has not been studied thoroughly.MethodsIn this study, we performed a prospective cohort study with 270 treated subclinical hypothyroidism patients undergoing their first IVF retrieval cycle at a single cite.ResultsSCH in women receiving LT4 replacement with a basal TSH level between 0.2-2.5mIU/L displayed a similar rate of clinical pregnancy (47.4% vs 38.7%, P = .436), miscarriage (7.4% vs 16.7%, P = .379) and live birth (43.9% vs 32.3%, P = .288) compared to women with a basal TSH level between 2.5-4.2 mIU/L.ConclusionStrictly controlled TSH (less than 2.5 mIU/L) before IVF may have no effect on the pregnancy rate in LT4 treated SCH women.

Role of thyrotropin-releasing hormone test in re-evaluation of congenital hypothyroidism

The thyrotropin-releasing hormone (TRH) test is useful for differentiating central and primary hypothyroidism, and is also valuable for diagnosing hypothyroidism. The threshold of the TRH test is usually set at 10–40 mIU/L. However, some experts are of the opinion that the TRH test has a limited role in evaluating hypothyroidism because of the clinical application of the new-generation thyroid-stimulating hormone (TSH) assay. We reviewed a case series to analyze the clinical use of the TRH test in the re-evaluation of congenital hypothyroidism. In total, data on 228 children with eutopic thyroid glands and neonatal hyperthyrotropinemia under levothyroxine replacement were collected. Basal TSH levels were measured and the TRH test was performed at the age of 3 years for re-evaluation of congenital hypothyroidism, and statistical analysis was performed. All of the patients were followed up to avoid over- or under-treatment. At the age of 3 years, 31.6% of the patients still had hypothyroidism. There was no significant difference between basal TSH level and TRH test in the diagnosis of hypothyroidism (p = 0.23). The negative predictive value of the basal TSH level was 100%, however, the positive predictive value was only 43.6%. When the TSH level was near the upper limit of the normal range (4.5–8.5 mIU/L), the TRH test result had a better correlation with hypothyroidism than the basal TSH level (p = 0.03). The threshold of the TRH test set at 60 mIU/L had the greatest area under the curve, with a negative predictive value of 95.2% and a positive predictive value of 80.2%. Neonatal hyperthyrotropinemia was a risk factor for hypothyroidism. We suggest that the TRH test should be administered in children with a basal TSH value near the upper limit of the normal range, and the threshold of the TRH test should be set at 60 mIU/L.

Subclinical hypothyroidism diagnosed by thyrotropin-releasing hormone stimulation test in infertile women with basal thyroid-stimulating hormone levels of 2.5 to 5.0 mIU/L.

ObjectiveTo investigate the prevalence of subclinical hypothyroidism (SH) diagnosed by thyrotropin-releasing hormone (TRH) stimulating test in infertile women with basal thyroid-stimulating hormone (TSH) levels of 2.5 to 5.0 mIU/L.MethodsThis study was performed in 39 infertile women with ovulatory disorders (group 1) and 27 infertile women with male infertility only (group 2, controls) who had basal serum TSH levels of 2.5 to 5.0 mIU/L and a TRH stimulating test. Serum TSH levels were measured before TRH injection (TSH0) and also measured at 20 minutes (TSH1) and 40 minutes (TSH2) following intravenous injection of 400 µg TRH. Exaggerated TSH response above 30 mIU/L following TRH injection was diagnosed as SH. Group 1 was composed of poor responders (subgroup A), patients with polycystic ovary syndrome (subgroup B) and patients with WHO group II anovulation except poor responder or polycystic ovary syndrome (subgroup C).ResultsThe prevalence of SH was significantly higher in group 1 of 46.2% (18/39) compared with 7.4% (2/27) in group 2 (P=0.001). TSH0, TSH1, and TSH2 levels were significantly higher in group 1 than the corresponding values in group 2 (P<0.001, P<0.001, P<0.001). In group 1, TSH1 and TSH2 levels were significantly lower in subgroup C compared with those in subgroup A and B (P=0.008, P=0.006, respectively).ConclusionTRH stimulation test had better be performed in infertile women with ovulatory disorders who have TSH levels between 2.5 and 5.0 mIU/L for early detection and appropriate treatment of SH.

Is there A Link between Serum Thyroid Stimulating Hormone Level and the Results of in vitro Fertilization and Embryo Transfer?

Objective To analyze the clinical features and outcomes in infertile patients with different levels of thyroid stimulating hormone (TSH) undergoing IVF/ICSI, and to investigate whether inappropriate level of TSH has the adverse effect on the results of the IVF-ET. Methods A total of 389 patients undergoing IVF/ICSI from January 2009 to December 2011 were divided into 3 groups according to the basal TSH level: group A (TSH 4.5 mIU/L). Oocyte retrieved, fertilization rate, cleavage rate, available embryo rate, pregnancy rate and miscarriage rate were analyzed to explore whether serum TSH level was correlated with the results of IVF/ICSI. Results There were no differences in number of oocyte retrieved, fertilization rate, cleavage rate and available embryo rate among 3 groups (P>0.05). Clinical pregnancy rate in group B (43.0%) was significantly higher than that in group A (30.2%) and group B (23.5%), respectively (P Conclusions TSH level has no effect on fertility rate or miscarriage rate in patients undergoing IVF/ICSI. Inadequacy TSH level would decrease the IVF/ICSI pregnancy rate.

Effects of long-term storage of filter paper blood samples on neonatal thyroid stimulating hormone, thyroxin and 17-alpha-hydroxyprogesterone measurements

Clinical laboratories store filter paper samples used in neonatal screening for various periods of time after performing hormonal measurements. However, due to lack of data concerning specimen stability, it is unclear for how long these samples should be stored. The objective of this study is to determine the stability and reproducibility of thyroid-stimulating hormone (TSH), thyroxine (T(4)) and 17-hydroxyprogesterone (17-OHP) measurements in filter paper blood samples stored for up to 60 months. Two hundred and twenty-eight blood samples, drawn between the second and the fourth day of life, were divided into seven distinct groups and kept at 4-8 degrees C for one day or 2, 12, 24, 36, 48 or 60 months after basal hormonal measurements. In each group, TSH, T(4) and 17-OHP levels were initially assayed 24-48 hours after collection (basal) and repeated once at the end of storage timing. All the measurements were performed by time-resolved fluorometry (1235 AutoDELFIA, Wallac Oy, Turku, Finland). Repeated and basal levels of each hormone were compared within the same group by Student's paired t-test. Differences were considered significant at P < 0.05. Compared with basal measurements, TSH and T(4) levels declined significantly only when these hormones were re-assayed at 48 or 60 months of sample storage. In contrast, 17-OHP concentrations decreased earlier, starting at 24 months and continuing throughout the remaining period. Our data suggest that neonatal screening of filter paper samples kept at 4-8 degrees C are reliable for repeating the hormonal measurements when specimens are stored for up to one year, in the case of 17-OHP, or three years, in the case of T(4) and TSH.

Thyroid function and volume in epileptic children using carbamazepine, oxcarbazepine and valproate

The aim of the present study was to investigate the effects of carbamazepine (CBZ), oxcarbazepine (OXC), and valproic acid (VPA) on thyroid function and volume in epileptic children. Fifty-three epileptic children (age, 3-17 years) treated with OXC (n = 10), CBZ (n = 12), or VPA (n = 31) at least for 1 year were evaluated in terms of thyroid hormones, thyroid-stimulating hormone (TSH) levels, response to thyrotropin-releasing hormone (TRH) stimulation test, and thyroid volumes. The patients in the OXC and CBZ groups had similar total thyroxin (TT4) and free T4 (fT4) median levels that were significantly lower than those of the VPA group (P < 0.016). Total tri-iodothyrosin median levels were lower in the CBZ group compared to the VPA group (P < 0.016). Basal TSH levels and thyroid volumes were similar in all groups (P > 0.016). One child from the OXC group (10%), one from the CBZ group (%8.3), and six from the VPA group (19.3%) had hypothyroidic status according to the TRH stimulation test. No statistically significant correlations were found between thyroid gland volume and thyroid function variables and between anti-epileptic drug receiving time and thyroid function or thyroid volume, respectively, in any of the groups (P > 0.05). Thyroid function should be evaluated periodically in children using CBZ, OXC or VPA. The children taking VPA seems to be at greater risk compared to children onr CBZ or OXC therapy. Except for the basal TSH values in the VPA group, the parameters predictive for the subclinical hypothyroid status remain to be evaluated in further studies.

Subclinical hypothyroidism in infertile women: The importance of continuous monitoring and the role of the thyrotropin-releasing hormone stimulation test

The aim of our study was to assess the prevalence of subclinical hypothyroidism (SH) after administering a thyrotropin-releasing hormone (TRH) stimulation test among women with normal serum thyroid-stimulating hormone (TSH) levels and various causes of infertility. Eighty-seven infertile women (39 with ovulation disorders and 48 with other causes of infertility) had a TRH stimulation test on day 3 – 7 of their cycle. Exaggerated TSH response (>30 mIU/l at 20, 40 or 60 min) following intravenous injection of 400 µg TRH was defined as SH. The TRH test was performed 2 – 4 months after the first visit to the clinic. We found that the prevalence of SH was significantly higher among women with ovulation disorders (20.5%) than among women with normal ovulation (8.3%). In addition, we found that although basal TSH levels were normal at recruitment, 2 – 4 months later these levels were abnormally high in 8% of the women. All these women had an abnormal TRH test. We recommend performing TRH stimulation testing in women suffering from ovulation disorders who have normal basal TSH levels, followed by repeat assessments of thyroid function to enable treatment with thyroxine in cases with abnormal results.

Thyroid Dysfunction in Adult Long-term Survivors After Hemapoeitic Stem-cell Transplantation (HSCT)

Thyroid function was evaluated in 72 adult survivors (41 females and 31 males) at 16 to 56 years of age, 1.5 years mean time (range 0.2 - 9.8) after hemapoeitic stem cell transplantation (HSCT) with no known prior history of thyroid dysfunction. Thyroid stimulating hormone (TSH) and free thyroxin levels (FT4) were determined before and after stimulation with thyrotropin releasing hormone (TRH). Conditioning regimens for HSCT did not include TBI. Overt hypothyroidism (basal TSH > 8 microIU/ml, FT4 < 0.8 ng/dl) was observed in 6% of male patients and 5% of female patients; subclinical hypothyroidism (basal TSH 4 - 8 microIU/ml, low normal FT4 0.8 - 1.9 ng/dl) was observed in 13% of males and 5% of females. A significant number of euthyroid patients (40% males and 54% females) with normal basal TSH and FT4 levels overresponded to TRH stimulation; the finding being statistically significant (p < 0.005). A heavy TSH response after TRH stimulation indicates compensated subclinical dysfunction of the thyroid gland. Chemotherapy-only conditioning regimens may have an adverse effect on thyroid gland function not always detected by determination of basal TSH and FT4 levels. This finding warrants long-term evaluation of thyroid function in HSCT patients.

Thyroid autoimmunity in children and adolescents with alopecia areata

Autoimmune thyroiditis (AT) is often associated with alopecia areata (AA) in children and adolescents. Forty-six children (23 girls and 23 boys), with a mean age of 9.9 +/- 3.38 years (2.24-17.5 years), were included in a study to assess thyroid function and thyroid autoantibody formation in AA. The size and function of the thyroid gland [triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), and thyrotropin releasing hormone (TRH) test; fluoroimmunologic assay (FIA), Delfia], antithyroglobulin (TAT) and antimicrosomal (MAT) antibodies (microhemagglutination method), thyroid gland ultrasound, and indices of cellular and humoral immunity were assessed. Thyromegaly was found in 29 children (63%). Increased basal TSH levels were present in six of the 29 (13.3%) and hypothyroid-type stimulated secretion (TRH test) in two (out of 12). TAT was increased in 17 (39.5%) and MAT in 14 (33.3%) children with AA. Thyroid ultrasound examination was suggestive of AT in 13 (34.2%) and typical of AT in five (13.2%) children. We diagnosed AT in 22 of 46 children with AA (47.8%). The immune studies revealed increased activated T lymphocytes. We recommend that thyroid gland size and function and antibody formation be examined at the diagnosis of AA and twice a year thereafter.

Clinical and Molecular Features of a TSH-Secreting Pituitary Microadenoma

We describe a case of a thyroid stimulating hormone (TSH)-secreting pituitary microadenoma, and report the systematic gene expression profile of the surgically- removed tumor. A 50-year-old woman was referred to our hospital because she had high TSH, free-T4, and free-T3 levels, and a pituitary tumor that was visualized with magnetic resonance imaging. Her basal TSH level was high even after a high T3 loading dose, and increased following administration of thyroid releasing hormone (TRH) even after administration of a high dose of exogenous T3. Her clinical symptoms and peripheral markers for T3 were responsive to exogenous T3. There was no thyroid hormone receptor (TR) beta gene mutation. The patient was diagnosed with a TSH-secreting pituitary adenoma, and trans-sphenoid surgery was performed. The histologic features and immunophenotype were consistent with a TSH-secreting pituitary adenoma. Reverse transcription-polymerase chain reaction analysis of pituitary hormones, pituitary-specific transcription factors, receptors, and transcriptional cofactors of clinical significance was performed on the removed tumor. The tumor expressed TSH, growth hormone, prolactin, alpha-subunit, pituitary transcription factor-1 (pit-1) but not proopiomelanocortin (POMC), prophet of pit-1 (prop-1) and pituitary cell-restricted T box factor (Tpit). TRbeta and TRH-receptor gene expression was normal. Three steroid receptor coactivators (SRC)-1, SRC-2, and SRC-3 were expressed. Nuclear receptor corepressor (N-CoR)2 was absent in the tumor, whereas nuclear receptor corepressor (N-CoR1) was expressed. Somatostatin receptor type 1 expression was significantly decreased, whereas type 4 receptor was expressed, which are unusual characteristics for pituitary tumors. The gene expression pattern in the tumor might have a role in the clinical features of this case.

Basal TSH levels compared with TRH-stimulated TSH levels to diagnose different degrees of TSH suppression: diagnostic and therapeutic impact of assay performance.

The estimated prevalence of endogenous subclinical hyperthyroidism varies from 4% to 6% and a basal thyroid stimulating hormone (TSH) level < 0.5 mU L-1 may be associated with increased mortality in subjects over 60 years of age who are not on thyroid medication. Exogenous TSH suppression is a mainstay in the treatment of thyroid cancer. Because of recent concerns about potential adverse effects, especially of endogenous TSH suppression on bone, the cardiovascular system and cognitive functions, subclinical hyperthyroidism obtained new clinical importance. We therefore re-evaluated the diagnostic value of basal and thyrotrop in TRH-stimulated serum TSH measurements using TSH assays with different sensitivities. A total of 805 oral and nasal TRH stimulation tests were performed on 409 ambulatory subjects with low basal serum TSH concentrations of less than 0.1 mIU L-1. Basal serum TSH was measured either using a second generation assay (functional sensitivity > 0.03 mIU L-1) or two third generation assays (functional sensitivity 0.01 mIU L-1 and 0.007 mU L-1, respectively). Serum TSH concentration was determined before and 3 h after oral administration of 40 mg of TRH and before and 30 min after nasal administration of 2 mg of TRH. In the oral testing group, the basal TSH levels measured by the different TSH assays were 0.06 +/- 0.03, 0.04 +/- 0.02 and 0.03 +/- 0.02, respectively, whereas the peak TSH levels were 0.4 +/- 0.6, 0.4 +/- 0.6 and 0.3 +/- 0.5 in the patients with subclinical hyperthyroidism. In overt hyperthyroidism, the basal TSH levels were 0.06 +/- 0.02, 0.03 +/- 0.02 and 0.03 +/- 0.02, whereas the peak TSH levels were 0.19 +/- 0.3, 0.16 +/- 0.3 and 0.15 +/- 0.2, respectively. Basal TSH values could discriminate between different degrees of TSH suppression if measured with a third generation assay (P < 0.001), but not with a second generation assay. There was only a weak correlation between basal TSH and peak TSH when measured by a second generation assay (n = 126; r = 0.3; P < 0.001) in contrast to the strong correlation found using the third generation assays (n = 128; r = 0.7; P < 0.001 and n = 69; r = 0.8; P < 0.001, respectively). In view of the recent concerns about potential adverse effects in TSH suppression and based on our data, it is mandatory to select a TSH assay with a functional sensitivity of < or = 0.01 mIU L-1 for optimal titration of L-T4 suppressive therapy, especially in patients with thyroid cancer. If, however, only a second generation TSH assay is available, additional TRH testing allows a more careful titration of suppressive thyroxine therapy.

Elevation of Serum Total Triiodothironine and Free Triiodothironine in Croatian Veterans with Combat-Related Post-Traumatic Stress Disorder

To asses possible differences in serum-free triiodothironine (FT3), total triiodothironine (TT3), free thyroxine, total thyroxine, and thyroid-stimulating hormone levels between male combat veterans with chronic post-traumatic stress disorder and healthy male control subjects. Male combat veterans (N = 38; ages 23-53 years; mean +/- SD = 35.9 +/- 7.5 years) with chronic post-traumatic stress disorder (duration of illness was 2-6 years; mean +/- SD = 3.53 +/- 0.95 years) were compared with healthy male control subjects (N = 32; ages 25-50 years; mean +/- SD = 36.5 +/- 8.3 years). Serum samples were analyzed by luminoimmunochemical assays for basal levels of thyroid-stimulating hormone, total thyroxine, TT3, free thyroxine, and FT3. Combat veterans with chronic combat-related post-traumatic stress disorder had significantly increased values of FT3 (mean +/- SD, 5.92 +/- 1.11; t = 2.27; p < 0.02), as well as TT3 (mean +/- SD, 2.04 +/- 0.32; t = 6.26; p < 0.0001) than the control group. Elevated serum TT3 and FT3 are associated with chronic combat-related post-traumatic stress disorder.

Training intensity influences leptin and thyroid hormones in highly trained rowers.

Leptin (L) is associated with body-weight-regulating and adipostatic functions. Its receptors also may be found centrally. Thyroid hormones regulate metabolic processes mainly by binding at peripheral receptors. Aim of this study was to show if there is a link between those central and peripheral regulation systems and to investigate the influence of different training intensities on L and the hypothalamic-thyroid-axis (HTA) in highly trained rowers. Six rowers (18.9 +/- 2.6 y; BMI 22.8 +/- 2.1 kg/m (2)) undertook high intensity resistance training (RT) for three weeks followed by three weeks of endurance training (ET). After each training cycle the subjects had one week for recovery (R1, R2). Blood samples were taken before and at the end of RT, R1, ET and R2. L, thyroid stimulating hormone (TSH), free T3 (fT3) and free T4 (fT4) were measured. After RT, a significant reduction in L, TSH and fT3 was found (p < 0.05). fT4 was unchanged. L remained decreased until the end of R1. After ET, a significant increase of TSH was found. L correlated to basal TSH levels (r = 0.49, p = 0.006) during R. BMI and body fat were unchanged throughout the study and were not correlated with hormonal levels. We speculate a high energy flux during intensified training (RT) caused the decrease of L and the HTA, independent of BMI or body fat. Thus, we conclude a depression of L and HTA is associated with training intensity.

Different neuroendocrine profiles of remitted and nonremitted schizophrenic patients

Background: Thyrotropin-releasing hormone (TRH) test and Dexamethasone Suppression Test (DST) are two neuroendocrine tests that have been extensively used in an attempt to predict treatment response and outcome in schizophrenia. The objectives of this study were to investigate (1) the relationship between TRH test and DST and various psychiatric symptoms and (2) the potential value of these tests in prediction of short-term outcome in schizophrenic patients. Methods: TRH test and DST were administered to 58 patients with schizophrenia. All patients were evaluated with a battery of rating scales before neuroendocrine test procedures and at regular intervals for 1 year. Patients were divided into two groups as remitted (RP; n=30) and nonremitted patients (NRP; n=28). Baseline results of these two groups were compared with each other and 30 healthy controls. Results: Basal levels of total T 3 (T 3T) and free T 3 (T 3F) were higher in RP group than controls. Basal prolactin (PRL) level was higher in RP group, but not in NRP, compared to controls. Basal growth hormone (GH) and thyroid-stimulating hormone (TSH) levels of NRP were significantly higher than those of RP. DST nonsuppression was observed at a significantly higher rate in RP than NRP and control group. Blunted TSH response rate in RP group was higher significantly compared to other two groups. Conclusions: The data implicate that higher basal TSH and GH levels may be associated with a poorer treatment response, whereas higher total and free T 3 levels, a blunted TSH response to TRH and nonsuppression on the DST may indicate a better response in schizophrenics.

Avaliação do eixo hipotalâmico-hipofisário-tireoidiano em crianças com síndrome de Down

To determine the thyroid stimulating hormone (TSH) secretion in children with Down syndrome (DS), who do not present clinical and laboratory evidence of classical hypothyroidism and concomitant undetectable antibodies. Fourteen children with DS with a mean age of 3.4 (+/- 1.8) years were studied. Patients with classical hypothyroidism or hyperthyroidism or those with positive antithyroid antibodies were excluded. The DS group was compared to a control group of 16 children with a mean age of 11.8 (+/- 3.8) years, diagnosed as having familial short stature or constitutional growth delay. Both groups underwent hormonal measurements at basal condition to determine serum TSH, T3, T4, free T4 and prolactin concentrations and after stimulation with thyrotropin releasing hormone (TRH). Thyroid hormones concentrations were also compared when children with DS were subdivided into two groups according to their basal TSH levels. Basal TSH and prolactin levels were significantly higher in DS group. After stimulation with TRH, TSH peak was higher in the DS group. The number of patients presenting basal TSH levels higher than 5 microU/mL and TSH peaks higher than 30 microU/mL were significantly higher in the DS group. Children with Down syndrome present frequent increase in basal TSH concentrations, despite the presence of normal basal thyroid hormones levels and negative antithyroid antibodies. Most of them (65%) show early intense response after TRH stimulation. Our data demonstrate that in spite of the absence of classic hypothyroidism and/or antithyroid antibodies, an abnormal pattern of TSH secretion occurred in patients with Down syndrome, possibly related to hypothalamic dysfunction.

Avaliação do eixo hipotalâmico-hipofisário-tireoidiano em crianças com síndrome de Down

To determine the thyroid stimulating hormone (TSH) secretion in children with Down syndrome (DS), who do not present clinical and laboratory evidence of classical hypothyroidism and concomitant undetectable antibodies.Fourteen children with DS with a mean age of 3.4 (+/- 1.8) years were studied. Patients with classical hypothyroidism or hyperthyroidism or those with positive antithyroid antibodies were excluded. The DS group was compared to a control group of 16 children with a mean age of 11.8 (+/- 3.8) years, diagnosed as having familial short stature or constitutional growth delay. Both groups underwent hormonal measurements at basal condition to determine serum TSH, T3, T4, free T4 and prolactin concentrations and after stimulation with thyrotropin releasing hormone (TRH). Thyroid hormones concentrations were also compared when children with DS were subdivided into two groups according to their basal TSH levels.Basal TSH and prolactin levels were significantly higher in DS group. After stimulation with TRH, TSH peak was higher in the DS group. The number of patients presenting basal TSH levels higher than 5 microU/mL and TSH peaks higher than 30 microU/mL were significantly higher in the DS group.Children with Down syndrome present frequent increase in basal TSH concentrations, despite the presence of normal basal thyroid hormones levels and negative antithyroid antibodies. Most of them (65%) show early intense response after TRH stimulation. Our data demonstrate that in spite of the absence of classic hypothyroidism and/or antithyroid antibodies, an abnormal pattern of TSH secretion occurred in patients with Down syndrome, possibly related to hypothalamic dysfunction.