The influence of perauorinated compounds (PFCs) on human health has increasingly been recognized. Recent studies have shown that PFCs are associated with the incidences of tumors, neurotoxicities, reproductive toxicity, and metabolic syndrome. However, the relationship between PFCs and thyroid diseases remains unclear. While some foreign studies have explored their potential correlations, the findings were still controversial due to different methodologies and populations. This article reviews the recent advances in the research on the relationship between PFCs and thyroid function.
Fluorocarbons ; Humans ; Thyroid Gland ; physiology

BACKGROUNDMaternal thyroid dysfunction is common during pregnancy, and physiological changes during pregnancy can lead to the overdiagnosis of hyperthyroidism and misdiagnosis of hypothyroidism with nongestation-specific reference intervals. Our aim was to compare sequential with nonsequential methods for the evaluation of thyroid function in pregnant women.

METHODSWe tested pregnant women who underwent their trimester prenatal screening at our hospital from February 2011 to September 2012 for serum thyroid stimulating hormone (TSH) and free thyroxine (FT4) using the Abbott and Roche kits. There were 447 and 200 patients enrolled in the nonsequential and sequential groups, respectively. The central 95% range between the 2.5th and the 97.5th percentiles was used as the reference interval for the thyroid function parameter.

RESULTSThe nonsequential group exhibited a significantly larger degree of dispersion in the TSH reference interval during the 2nd and 3rd trimesters as measured using both the Abbott and Roche kits (all P < 0.05). The TSH reference intervals were significantly larger in the nonsequential group than in the sequential group during the 3rd trimester as measured with both the Abbott (4.95 vs. 3.77 mU/L, P < 0.001) and Roche kits (6.62 vs. 5.01 mU/L, P = 0.004). The nonsequential group had a significantly larger FT4 reference interval as measured with the Abbott kit during all trimesters (12.64 vs. 5.82 pmol/L; 7.96 vs. 4.77 pmol/L; 8.10 vs. 4.77 pmol/L, respectively, all P < 0.05), whereas a significantly larger FT4 reference interval was only observed during the 2nd trimester with the Roche kit (7.76 vs. 5.52 pmol/L, P = 0.002).

CONCLUSIONSIt was more reasonable to establish reference intervals for the evaluation of maternal thyroid function using the sequential method during each trimester of pregnancy. Moreover, the exclusion of pregnancy-related complications should be considered in the inclusion criteria for thyroid function tests.

Female ; Humans ; Pregnancy ; physiology ; Reference Values ; Thyroid Gland ; physiology ; Thyrotropin ; blood ; Thyroxine ; blood

Thyroglobulin is the most important and abundant protein in thyroid follicles and has been widely studied as a tumor marker of thyroid cancer recurrence and persistence. Tg is considered the material basis of thyroid hormone synthesis and does not participate in the regulation of thyroid hormone synthesis and secretion. This review summarizes the recent progress in the research of thyroid hormone synthesis and secretion regulation via a negative feedback regulation mechanism by the thyroid-hypothalamus-pituitary axis. Thyroglobulin can negatively regulate the synthesis of thyroid hormone by thyroid follicular cells and antagonize the positive regulation of thyrotropin TSH. The function of thyroid follicular cells is presumably a result of Tg and TSH interaction, and a follicular cycle model is proposed to explain the causes of follicular heterogeneity in glands. We also discuss the prospects and clinical significance of studies into the negative feedback regulation mechanism of the thyroid-hypothalamus-pituitary axis and compare two theories for this mechanism.
Feedback, Physiological ; Humans ; Hypothalamo-Hypophyseal System ; physiology ; Neoplasm Recurrence, Local ; Thyroglobulin ; metabolism ; Thyroid Gland ; physiology ; Thyroid Hormones ; metabolism ; Thyrotropin ; metabolism

OBJECTIVETo study iodine nutrition of pregnant women in different occasions and thyroid function of their neonates.

METHODSUrinary iodine of pregnant women and their serum T(3), T(4), FT(3), FT(4) were determined by chloric acid-digestion thermostatic assay and RIA, TSH determination by IRMA; neonatal umbilical cord blood TSH was determined by ELISA.

RESULTSMedian urinary iodine of pregnant women were 206.3 microg/L, 161.4 microg/L, 203.3 microg/L at 10 - 14 (first occasion), 23 - 27 (second occasion) and 39 - 40 (third occasion) week but the percentage that lower than 100 microg/L were 14.6%, 17.1%, 11.1% respectively. Serum T(3), T(4) of pregnant women was significantly higher than those women of premarital health inspection (PHIW, P < 0.001). The difference of serum T(3), T(4) of pregnant women at 10 - 14 and 39 - 40 week was not significant. Serum FT(3), FT(4) of pregnant women at 39 - 40 week were 2.61 +/- 0.47 pmol/L and 5.50 +/- 1.57 pmol/L respectively. The difference of serum TSH concentration at third occasion and first occasion of pre-pregnancy was significant but the difference of TSH frequency distribution in three groups was not significant (chi(2) = 1.138, P > 0.5). Blood TSH median neonatal umbilical cord was 1.99 mU/L but the percentage that higher than 5 mU/L was 9.4%.

CONCLUSIONFor those areas with high iodized salt coverage, pregnant women had had sufficient iodine supplement and good thyroid function. The percentage of neonates from iodine sufficient pregnant women with TSH > 5 mU/L was lower than 10%. Using the normal range of nonpregnant FT(3) and FT(4) to estimate the thyroid function of pregnant women could cause mis diagnosis.

Female ; Fetal Blood ; chemistry ; Humans ; Infant, Newborn ; Iodine ; urine ; Pregnancy ; Thyroid Gland ; physiology ; Thyroid Hormones ; blood ; Thyrotropin ; blood

Thyroid disease is common in young women, and thus frequently managed in pregnancy, affecting 1% to 2% of pregnant women. Pregnancy may modify the course of thyroid disease, and pregnancy outcomes can depend on optimal management of thyroid disorders. Moreover, thyroid autoantibodies have been associated with increased early pregnancy wastage, and uncontrolled thyrotoxicosis and untreated hypothyroidism are both associated with adverse pregnancy outcomes. Consequently, obstetric providers must be familiar with thyroid physiology, as well as screening and management of thyroid diseases in pregnancy. Following a brief overview of physiology, this article provides a review of the diagnosis and management of the spectrum of thyroid disease occurring in pregnancy.
Autoantibodies ; Diagnosis ; Disease Management ; Female ; Humans ; Hypothyroidism ; Mass Screening ; Physiology ; Pregnancy Outcome ; Pregnancy* ; Pregnant Women ; Thyroid Diseases* ; Thyroid Gland* ; Thyrotoxicosis

Disorders derived from abnormal prolactin(PRL) production are relatively common ingynecological practice. Infertility, menstrual disorders, and galactorrhea are the most frequentmanifestations encountered in women. And, although frequently benign, the disordersoccasionally may have severe consequences.We studied 341 infertile women with normal menstruation(N group) and 105 womenwith oligomenorrhea(O group) and 70 women with secondary amenorrhea(A group), first; to investigate the prevalence of hyperprolactinemia(hPRL) and its clinical etiologies in 3groups, second; to estimate the effect of the bromocriptine(BRMC) treatment in N group,and finally; to obtain an understanding of the underlying physiology and pathoghysiologycoupled with the awareness of the hetrogeneous presentation of hPRL from June, 1994 toDecember, 1996.The results of this study were as follows;1. There were no significant correlations of serum PRL levels by ages in 3 groups.2. The prevalence rates of conventional hPRL(PRL>25ng/mL) were 18.2% in N group,22.9% in O group, 28.6% in A group and were not different among 3 groups(P=0.12).But the rates of PRL>50 ng/mL were 4.7%, 7.6%, 20.0%, respectively and were different(p < 0.01).3. The most common causes of hPRL were prolactinomas(9.3%) and thyroid disorders(4.7%) except the undiagnosed(72.1%).4. The cumulative pregnancy rates of 6~24 months duration were not different betweenBRMC-treated women(33.3%) and BRMC-untreated women(38.9%) in N group(p=0.92).
Female ; Galactorrhea ; Humans ; Hyperprolactinemia* ; Infertility ; Physiology ; Pregnancy ; Pregnancy Rate ; Prevalence ; Thyroid Gland

OBJECTIVETo explore the effects of lead on the thyroid function of occupationally exposed workers.

METHOD157 workers occupationally exposed to lead in a smelting factory were investigated. The concentration of lead in air at workshop was measured by flame atomic absorption spectrophotometry (FAAS) and the levels of blood lead (PbB) by atomic absorption spectrophotometry (AAS), zinc protoporphyrin (ZPP) by ZnPP meter, as well as the indexes of thyroid function, thyroid-stimulating hormone (TSH), triiodothyronine (T(3)), thyroxin (T(4)), free T(3) (FT(3)), and free T(4) (FT(4)) in serum by radioimmunoassay.

RESULTSThe workers with higher level of blood lead (> 2.88 micro mol/L) showed lower levels of T(3) [(1.54 +/- 0.39) nmol/L] and FT(3) [(5.50 +/- 1.26) pmol/L] than those with lower blood lead level [PbB: (1.92 approximately 2.88) micro mol/L group, T(3): (1.71 +/- 0.45) nmol/L, FT(3): (6.12 +/- 1.64) pmol/L, P < 0.05]. There was no obvious effect of length of service on thyroid hormone of exposed workers.

CONCLUSIONHigher level of blood lead may cause certain damage to thyroid function by inhibiting deiodination of T(4). No obvious relation between length of service and thyroid function was found.

Adult ; Female ; Humans ; Lead ; blood ; toxicity ; Male ; Middle Aged ; Occupational Exposure ; Thyroid Gland ; drug effects ; physiology

BACKGROUNDThe importance of diagnosis of thyroid dysfunction during pregnancy has been widely recognized. Our study was designed to compare two different detection reagents between Abbott and Roche and to establish the gestational related reference intervals for thyroid function tests (TFT) in Chinese women and to assay the reference ranges with the American Thyroid Association recommended standard.

METHODSSerum samples were collected from 693 normal pregnant Chinese women and divided into five groups according to their gestational age: 9-13, 16-20, 24-28, 32-34 and 37-40 weeks. Thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels were determined by two different detection reagents: Abbott Architect I 2000 and Roche Cobas Elecsys 600. The reference ranges of the TFT indexes were calculated according to the National Academy of Clinical Biochemistry (NACB). The 2.5th and 97.5th percentiles of each stage were calculated, and the results were analyzed by one-way analysis of variances, t-test, and Spearman correlation analysis.

RESULTSThyroid hormone levels varied greatly among different gestational stages. TSH levels, as assessed via two different TSH ELISA kits showed consistent changing pattern during pregnancy and displayed linear correlation (P < 0.001). In 9-13 gestational weeks, TSH levels were significantly lower than that of other groups; and in 37-40 gestational weeks, it was higher than that of other groups (all P < 0.001). TSH reference ranges determined by Roche detection reagent in each group were higher than those by Abbott detection reagent (P < 0.01 respectively). FT4 levels were higher in 9-13 gestational weeks than that of other groups (P < 0.001). FT4 levels determined by Roche reagent were higher than Abbott reagent in 9-13 weeks, (P < 0.001), and lower in 24-28 and 37-40 weeks (P < 0.001 and P = 0.016, respectively). The TSH level was correlated with FT4 levels in 9-13 gestational weeks by detection reagents (for Abbott reagent, r=-0.319 for FT4 P < 0.001; for Roche reagent, r=-0.352 for FT4, P <0.001).

CONCLUSIONAccurate evaluation of TFT in pregnant women should be based on the gestational-related reference intervals in Chinese population, and different detection reagents should also establish their own reference intervals.

Adult ; Female ; Gestational Age ; Humans ; Luminescent Measurements ; Pregnancy ; physiology ; Reference Values ; Thyroid Function Tests ; Thyroid Gland ; physiology ; Thyrotropin ; blood ; Thyroxine ; blood

This study was performed to observe the changes of blood sugar levels in 200 cases with acute Carbon monoxide (CO) poisoning. Successive tests of blood sugar on the day of onset and the lst, 2nd, 3rd & 4th day after anoxic insult were done in 12 patients with acute CO poisoning. In addition, to determine the derangement of thyroid function, blood levels of triiodothyronine(T3), tetraiodothyronine(T4), thyroid-stimulating hormone (TSH) were measured on the day of admission in 29 with C0 poisoning. The blood levels of T3, T4 and TSH were within normal ranges, but over two-thirds were distributed in lower range of normal mean values. This lower tendency within normal range was especially prominent in the blood level of T3. The blood level of sugar was increased, and 79.5% was higher than the upper limit of normal range. The blood levels of T3 and T4 were significantly decreased as CO exposure time period- prolonged. There was significant negative correlation between blood T3 levels and consciousness levels. Blood TSH levels were not significantly affected in acute CO poisoning. As consciousness levels were depressed and exposure time period were prolonged, blood sugar was increased. There found a rapid increase in blood sugar, followed by a abrupt dropping, and then progressive decrease to normal level over a period of 5 days after exposure to CO. In conclusion, acute CO poisoning obviously changes the thyroidal physiology. Even though blood TSH levels were variable, there was an obvious decrease in T3. The assumed CO-induced decrease in thyroid hormone secretion is seemingly not mediated by depressed TSH secretion but thyroid hormone metabolic dysfunction or extrathyroidal cotiverslon defect The alterations of blood sugar were also found to be acute and temporal which may be the result of physiologic compensation to hypoxic state caused by CO poisoning.
Blood Glucose ; Carbon Monoxide Poisoning* ; Carbon Monoxide* ; Carbon* ; Compensation and Redress ; Consciousness ; Humans ; Physiology ; Poisoning ; Reference Values ; Thyroid Gland* ; Thyroid Hormones* ; Thyrotropin

BACKGROUND: Systemic inflammatory reaction syndrome (SIRS) describes the systemic inflammatory process and can be seen following a wide variety of insults. This is the leading cause of morbidity and mortality for patients admitted to the ICU. The arterial keton body ratio (AKBR), serum lactate level and the thyroid hormones, thyroid stimulation hormone (TSH), thyroxine (T4), free thyroxine (FT4) and triiodothyronine (T3) deteriorate in critically ill patients with a poor prognosis. The APACHE (Acute Physiology, and Chronic Health Evaluation) III and multiple organ failure (MOF) score have been known as good prognostic predictors in the ICU. The object of this study was to compare the AKBR, lactate and thyroid hormone levels, and the APACHE III and MOF score between the survivors (SV) and nonsurvivors (NSV) and the correlation among the above predictors. METHODS: 35 patients with no known thyroid or liver disease who were admitted to the SICU with the criteria of SIRS were selected. Arterial blood was drawn for the AKBR, and the lactate and thyroid hormones studies. The APACHE III and MOF scorings were done in the first 24 hours of SICU admission. RESULTS: There were no significant difference between SV and NSV except APACHE III (SV: 68.7 24.6, NSV; 92.9 27.6). There were significant correlations between the APACHE III and MOF score (R = 0.688, P<0.01), APACHE III and lactate (R = 0.575, P<0.01), and MOF score and lactate (R =0.483, P<0.01). Thyroid hormones had positive correlations among themselves only. CONCLUSIONS: We conclude that APACHE III is the only good predictor of mortality. The APACHE III, MOF score, and lactate level show good correlations indicating the severity in condition of the ICU patients.
APACHE ; Critical Illness ; Humans ; Lactic Acid ; Liver Diseases ; Metabolism* ; Mortality ; Multiple Organ Failure ; Physiology ; Prognosis ; Survivors ; Thyroid Gland* ; Thyroid Hormones* ; Thyroxine ; Triiodothyronine