• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.293-298
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• 1991

A study was conducted to determine the effect of environmental temperature and level of food intake on plasma concentration of thyroid hormones. Three dairy heifers were used in an experiment which consisted of three levels of chamber temperature (10, 20 and $30^{\circ}C$) and three levels of food intake (100, 75 and 50% of recommended requirements). The analysis showed significant effects of environmental temperature on plasma triiodothyronine concentration, rectal temperature, respiration rate and heart rate but not on heat production. The range of plasma triiodothyronine was 2.51~1.79 ng/ml when the environmental temperature varied from 10 to $30^{\circ}C$. Effects of feed intake level were significant for heart rate and heal production. Heat production decreased from 25.9 to $20.0kJ/kg^{0.75}{\cdot}h$ when the TDN intake decreased from 66.3 to $35.1g/kg^{0.75}{\cdot}d$. There was no interactive effect of environmental temperature and feed intake level. Plasma triiodothyronine concentration decreased under high environmental temperature without any changes in heat production. The effects of environmental temperature and feed intake level on the physiological function of thyroid gland, as indicated by the relative circulating rate of thyroid hormones, were found to be clear.

• Nutritional Sciences
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• v.8 no.3
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• pp.196-199
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• 2005

A study during second trimester of pregnancy was conducted among 100 women from a population with mild to moderate deficient iodine intake (median 7 ${\mu}g$/L)to monitor the changes in serum free thyroxin ($FT_4$), triiodothyionine ($T_3$) and thyrtropin (TSH). Thyroid related hormones were assessed using radioimmunoassay (RIA) and immunoradiometricassay (IRMA). As compared with non pregnant women, mean $FT_4$ levels decreased, $T_3$ levels increased and TSH levels were slightly depressed in pregnant women. Mean $FT_4$ concentration reached its highest level in the $4^{th}$ month and linearly decreased until the $6^{th}$ month. Mean $T_3$ level remained almost constant during $2^{nd}$ trimester of pregnancy. Mean TSH level remained unaltered during the $4^{th}$ and $5^{th}$ months and was slightly lower than that for the control group. However, these differences were statistically insignificant At the end of the second trimester, hypothyroxinemia and $T_3$ levels greater than the upper limit of the laboratory reference range were found in $34\%$ and $38\%$ of women, respectively. These changes in thyroid hormones reflect typical adaptations of the thyroid gland during pregnancy to the limited availability of iodine.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6643-6647
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• 2014

The breast and the thyroid are hormone responsive organs that are closely related with changes of endocrine function and glandular disease. An association between thyroid disorders and breast cancer (BC) risk has been suggested, although the results are inconclusive. The purpose of the present study was to summarize evidence supporting a relationship between BC and the level of thyroid hormones and antibodies. The MEDLINE and EMBASE electronic databases were searched for studies published between 2000 and 2014. The pooled effects were presented as weighted mean differences (WMD) with 95% confidence intervals (CI) using fixed or random effect models. We summarized the results of 8 cross-sectional studies with 4, 189 participants. The overall pooled results showed that the levels of $FT_3$ and $FT_4$ were significantly increased in patients with BC (WMD=1.592 pmol/l; 95% CI: 0.15-3.033 and WMD=0.461 ng/dl; 95% CI: 0.015-0.906; p=0.043). The TPOAb level in patients with BC was higher than that in the control group (WMD=81.4 IU/ml; 95% CI: 78.7-84.0; p=0.000). The overall pooled results of the TgAb with random effects analyses showed that the TgAb level was significantly increased in patients with BC (WMD=101.3 IU/ml; 95% CI: 48.7-153.9; p=0.000). The present results indicated that the serum levels of $FT_3$, TPOAb and TgAb are significantly higher in patients with breast cancer than in healthy controls.

• The Korean Journal of Nuclear Medicine
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• v.17 no.1
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• pp.63-69
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• 1983

Fifteen cases of Korean hemorrhagic fever who were admitted Chungnam National University Hospital from October 1981 to December 1981 were analysed on the evaluation of metabolic.changes of the thyroid hormones, and thyroid function status in each clinical phase. 1. Serum $T_3,\;T_4$ concentratron, $FT_4I\;and\;T_4/TBG$ ratio were significantly lower (p<0.001, p<0.005, p<0.005, p<0.001, respectively) than control group in oliguric and early diuretic phase of Korean hemorrhagic fever. With the recovery of illness, abnormal thyroid hormones and thyroid function indices tend to become normal range. But Serum $FT_4$, TSH and TBG concentration were within normal range in all phase of KHF. Thus in Korean hemorrhagic fever, euthyroidism is probably maintained by normal or elevated serum $FT_4$ 2. $T_4/T_3\;and\;rT_3/T_3$ rato (p<0.005, p<0.005) were increased in oliguric and early diuretic phase of KHF. These results might be explained by decreased peripheral conversion of $T_4\;to\;T_3$ in oliguric and early diuretic phase.

• Toxicological Research
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• v.35 no.1
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• pp.9-12
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• 2019

One of the major challenges in methadone maintenance therapy (MMT) for drug dependence is the physiological side effects on endocrine hormones. Because of the key role of the thyroid gland in the normal functioning of the human body and brain, this study examined the effect of MMT on thyroid function. Thyroid hormones (T3, T4, and thyroid-stimulating hormone (TSH)) were evaluated in normal and user treated with MMT who were referred to the Province Clinical & Pathology Center of Urmia, Iran. The study was conducted for three months using the Case Series method. A total of 270 samples were collected, 215 were from individuals who were not treated, whereas 55 were from men treated with methadone. Average levels of T3 and T4 in non-treated sample of men are $1.34{\pm}0.02ng/mL$ and $90.96{\pm}1.38ng/mL$ while the corresponding values for patients treated with methadone are $1.39{\pm}0.04ng/mL$ for T3 and $94.57{\pm}2.72ng/mL$ for T4. Mean TSH levels of the non-treated group and the methadone consuming group were $1.75{\pm}0.08{\mu}IU/mL$ and $3.17{\pm}0.45{\mu}IU/mL$, respectively. These results indicate that although men treated with methadone had higher levels of T3, T4, and TSH than normal individuals, only the difference in TSH level was significant. The importance of this difference among individuals on methadone maintenance programs should be investigated in larger samples over long periods of time. Additionally, the effects of methadone treatment on women should be examined.

• Analytical Science and Technology
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• v.20 no.5
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• pp.424-433
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• 2007

An analytical method for the determination of thyroid hormones in plasma samples has been studied by solid-phase extraction and high-performance liquid chromatography/diode array detector (DAD)/electrospray ionization (ESI)-mass spectrometer. Seven thyroid hormones were successfully separated by gradient elution on the reverse phase Hypersil ODS column (4.6 mm I.D., 250 mm length, particle size $5{\mu}m$) with ammonium formate buffer and acetonitrile. In addition, these compounds were confirmed by UV spectra and ESI-mass Spectra. The extraction recoveries of thyroid hormones in the plasma sample (at pH 3) were in the range of 74.5-115.7 % with solid-phase extraction by C18, followed by elution with 4 mL of methanol. The calibration curves showed good linearity with the correlation coefficients ($r^2$) varying from 0.9939 to 0.9978 and the detection limits of all analytes were obtained in the range of 20-50 ng/mL (38.1-162.8 pmol/mL). As a result, thyroxine was found in the range of 50.98-112.97 ng/mL in normal plasma samples.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.936-941
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• 2004

Four rumen-cannulated cows (330 kg average weight at 4 years) were used to evaluate the supplement of ensiled cassava tops (ECT) (variety KM 94, 39% DM) on rumen functions, thyroid hormones and liver enzymes. The treatments, arranged in a 4 $\times$4 Latin square design, were ECT at 0, 50, 100 and 150 g CP 100 kg$^{-1}$ body weight (BW), and a basal diet of urea-treated fresh rice straw (UFRS) ad libitum and 1.1 kg dry matter (DM) cassava root meal (CRM) in each 30 day study period. The results showed a continuous decrease in dry matter intake (DMI) of UFRS with increasing level of ECT supplement (p<0.001). The highest total DMI was observed for treatment ECT$_{150}$ (2.68 kg DM 100 kg$^{-1}$ BW day$^{-1}$) followed by treatments ECT$_{100}$, ECT$_{50}$ and ECT$_{0}$, with 2.47, 2.24 and 2.06 kg DM 100 kg$^{-1}$ BW⋅day$^{-1}$, respectively. Increasing levels of ECT supplement increased the concentration of total volatile fatty acids (p<0.05) and ammonia nitrogen (p<0.05) and resulted in a decrease in pH (p<0.05). Overall average plasma triiodothyronine and thyroxine concentrations were 0.80, 0.82, 0.85 and 0.69 ng ml$^{-1}$ (p>0.05), and 50.9, 49.5, 50.7 and 42.4 ng ml-1 (p>0.05) for treatments ECT$_{0}$, ECT$_{50}$, ECT$_{100}$ and ECT$_{150}$, respectively. There were non-significant differences in alanine aminotransferase and aspartate aminotransferase among treatments. It is concluded that ECT is a valuable protein-rich feed supplement to cattle, and the highest level of on average 2.48 kg DM ECT per cow and day (28% of total DMI) did not significantly affect thyroid gland hormones and liver enzymes in cows.

• Korean Journal of Veterinary Research
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• v.54 no.3
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• pp.165-169
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• 2014

The present study compared leptin, adiponectin, and thyroid hormone concentrations in normal and obese dogs, and evaluated the association between leptin and adiponectin concentrations and thyroid function. The serum leptin, adiponectin, thyroid-stimulating hormone (TSH), total thyroxine (tT4), free thyroxine (fT4), triiodothyronine (T3), and cortisol concentrations were measured in 18 normal dogs (body condition score [BCS]: 4-5/9) and 16 obese dogs (BCS: 8-9/9). Leptin and T3 concentrations were higher in the obese group than the normal weight group (p < 0.01 and p < 0.05, respectively). In both groups, the T3 and leptin concentrations were correlated (r = 0.370, p < 0.05), as were the TSH and fT4 and adiponectin concentrations (r = -0.373, p < 0.05 and r = 0.369, p < 0.05, respectively). In the normal weight group, the TSH and fT4 concentrations were correlated with the adiponectin concentrations (r = -0.528, p < 0.05 and r = 0.482, p < 0.05, respectively). The results of the present study suggest that leptin and T3 concentrations are significantly higher in obese dogs than normal weight dogs, and the serum T3 and leptin concentrations are positively correlated.

• Journal of Preventive Medicine and Public Health
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• v.54 no.1
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• pp.37-45
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• 2021

Objectives: Bisphenol A (BPA) is used in the electrical, mechanical, medical, and food industries. Previous studies have suggested that BPA is an endocrine disruptor. Regulation of BPA has led to increased use of bisphenol F (BPF) and bisphenol S (BPS). However, few studies have investigated the associations of BPF and BPS with thyroid dysfunction in children. Our study investigated the associations of prenatal BPA and early childhood BPA, BPF, and BPS exposure with thyroid function in 6-year-old children. Methods: Prenatal BPA concentrations were measured during the second trimester of pregnancy in an established prospective birth cohort. We measured urinary BPA, BPF, and BPS concentrations and thyroid hormone levels (thyroid-stimulating hormone, total T3, and free T4) in 6-year-old children (n=574). We examined the associations between urinary bisphenol concentrations and percentage change of thyroid hormone concentrations using multivariate linear regression. We also compared thyroid hormone levels by dividing the cohort according to BPA, BPF, and BPS concentrations. Results: The associations between prenatal BPA and total T3 levels were statistically significant in all models, except for girls when using a crude model. The associations between urinary BPA and BPS concentrations and levels of all thyroid hormones were not statistically significant. However, we observed that lower free T4 levels (-1.94%; 95% confidence interval, -3.82 to -0.03) were associated with higher urinary BPF concentrations in girls only. Conclusions: Our findings identified significant associations between prenatal BPA exposure and total T3 levels in all children and between BPF exposure and free T4 levels in girls only.

• The Korean Journal of Pharmacology
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• v.17 no.2
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• pp.37-45
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• 1981

The importance of thyroid hormones for the survival of rats in the cold is along-established fact. Hypothyroid animals are unable to survive in a cold environment. It was also reported that acute exposure of rats, guinea pigs and rabbits to cold produced an increased secretion of TSH and thereby thyroid hormone secretion within 10 to 30 min, but this increase of thyroid activity disappeared quite rapidly during warming. However, in human study no significant difference was found in the concentration of $T_4$, TSH and cortisol between summer and winter. But plasma $T_3$ concentration was increased significantly in winter in 56 adult men. On the other hand, it has been also known that catecholamines are important in the maintenance of body temperature of rat exposured to cold. Abundant evidences suggest that the sympathetic nervous system is involved in the activation of nonshivering thermogenesis and that thyroid hormone metabolism and secretion are influenced by catecholamines and consequently by the activity of the sympatheticadrenal system. Many of the metabolic effects of catecholamines are associated with an increase in the level of cAMP mediated through activation of adenylate cyclase which converts ATP to cAMP. Other studies have shown that thyroid hormones affect the amount of adenylate cyclase present in the adipose tissue. On the other hand. it was also reported that a particulate cAMP phosphodiesterase activity in fat cells was modulated by the action of thyroid hormones. The objective of the present study was to determine the interaction between thyroid activity and cyclic nucleotides during acute exposure to cold. Albino rats weighing around 200 g were used as the experimental animal. The room temperature group was kept at $25^{\circ}C$ and the cold-exposured group was kept at $4^{\circ}C$ for 1 week or 2 weeks. Each group was subdivided into three subgroups; control, KI, and MTU group. At the end of experiment the animals were etherized and blood was taken from abdominal aorta for $T_4,\;T_3$ and cyclic nucleotides. The determinations of $T_3,\;T_4$ and cyclic nucleotides were carried out with a radioimmunoassay(RIA) method. The results were summerized as followings. 1) A significant increase of thyroid weight was observed in rats exposured to cold for 2 weeks. Furthermore, in rats administered MTU while to exposure to cold the thyroid weight was also increased significantly. 2) After 2 weeks $T_3$ concentration in the plasma of cold-exposured rats was significantly increased in KI group and MTU group as well as in control group. On the contrary, after 2 weeks of cold exposure $T_4$ level was decreased in control group. 3) In the case of cyclic nucleotides, plasma cAMP was increased in the control group after 1 or 2 weeks of cold exposure. However, cAMP level in plasma was rather significantly decreased in KI group and MTU group as well as in control group.