Alteration in tissue and serum concentrations of TSH, iodide, T4 and T3 induced by various dietary iodide levels.

Isotopic equilibrium and radioimmunoassay methods were used to evaluate the effects of increases in iodide intake on tissue and serum concentrations of thyroid hormones. Within the range of iodide levels used total iodine in peripheral tissues and serum increase directly with iodide intake but this change is mainly due to an increase in inorganic iodide. It is concluded that increases in tissue thyroid hormone concentrations occur within a relatively narrow range of iodide intake and maximal concentration occurs at an iodide intake of 3-10 mug/day.     

Serum T3, T4, FT3, TSH and TBG in Turner's syndrome]

Turner's syndrome was originally reported as sexual infantilism, short stature, webbed neck and cubitus valgus. Subsequent investigations, however, have disclosed many other abnormalities both in chromosomal and physical features occurring in this syndrome. An increased prevalence of Hashimoto's thyroiditis in patients with Turner's syndrome has been well documented and molecular defects of the TBG have been described. In our study we examined serum T3, T4, FT3, FT4, TSH and TBG levels in 18 girls with Turner's syndrome, in 18 healthy control girls and in the parents of both groups. We reported significant elevated levels of T3 and FT3 in the Turner's group (P 0.01). We did not find any quantitative abnormalities of immunoreactive TBG in the same patients.     

Serum TSH, T4, T3, FT4, FT3, rT3, and TBG in youngsters with non-ketotic insulin-dependent diabetes mellitus

Several parameters of thyroid function were studied in 112 non-ketoacidotic youngsters with insulin-dependent diabetes mellitus (IDDM). Levels of thyroxine (T4), reverse triiodothyronine (rT3), thyroxine-binding globulin (TBG) and T3 were lower than in controls, whereas FT4, and FT3 were normal. T4 levels in IDDM patients were positively related to T3, rT3 and TBG, and inversely related to haemoglobin A1 (HbA1). However, only 4 patients showed biochemical hypothyroidism (T4 less than 5 micrograms/100 ml), whereas their FT4, FT3 and thyroid-stimulating hormone (TSH) levels were normal. Concurrent variations of T3 and rT3 levels were found in IDDM patients; thus, their T3/rT3 ratios were stable or higher than in controls, indicating that peripheral deiodination of T4 is preferentially oriented to production of rT3 only during ketoacidosis. Although changes in thyroid function may reflect the degree of metabolic control of diabetes in a large population, the clinical usefulness of serum thyroid hormone measurements in an individual case still appears to be limited.     

Influence of experimental acidosis on the concentrations of thyreostimulin (TSH) and iodothyronines (total T4, free T4, T3) in the plasma of the newborn lamb

The effects of acute acidosis on neonatal thyroid function were studied by infusing HCl for 4 h in 42 to 54-h-old lambs. Animals of the same age, used as controls, were simultaneously infused with physiological saline. HCl infusion induced a sharp decrease in blood pH and total restoration did not occur before 48 h. When compared to control lambs, this experimental acidosis was associated with slight, but significant, decreases in plasma TSH, total T4, free T4 and total T3 levels, and in values of the free T4/total T4 ratio; the T3/FT4 ratio was not affected. The values of RT3/FT4 ratio were significantly increased in acidotic lambs. It is concluded that acidosis induced only modest secretory changes in neonatal thyroid function and slightly reduced the proportion and the amount of free T4.     

Serum T(4) and serum T(3) concentrations in immature captive whitetip reef sharks, Triaenodon obesus.

Serum T(3) (3,5,3' triiodothyronine) and serum T(4) (thyroxine) concentrations were repetitively assayed by radioimmunoassay over a three-year period in two male and two female immature captive whitetip reef sharks, Triaenodon obesus. These sharks were maintained at the Waikiki Aquarium, Honolulu, Hawaii, in an open system holding pool receiving 568 liters per minute of water from a saltwater well with an iodide concentration of 0.076 mg/liter. No significant male-female difference was observed for either serum T(3) or serum T(4). No seasonal pattern of serum T(3) was detected (P = 0.07). Serum T(3) concentrations ranged (mean +/- SEM) from 0. 52 to 0.83 ng/mL (0.67 +/- 0.01; n = 64). A significant seasonal difference was observed for serum T(4) (P < 0.001). Serum T(4) concentration was higher in winter (October-January) with a mean (range +/- SEM) of 6.58 ng/mL (1.48-8.77 +/- 0.35; n = 24) and lower in summer (May-August) with a mean of 3.62 ng/mL (1.34-5.71 +/- 0. 22; n = 24). The thyroid hormone T(4) has a seasonal rhythm even in immature sharks and may have an important role in physiology. J. Exp. Zool. 284:500-504, 1999.     

Blood serum triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH) concentrations in healthy children at the age of 1 and 2 years

The physiological mean concentrations of T3, T4 an TSH in 150 healthy children aged from 1 month to 2 years of life decreased gradually with age. The statistically significant difference was observed only in T3 levels between the first and second year of life. The remaining parameters did not show statistically significant differences.     

Behaviour of serum T3, rT3, TT4, FT4 and TSH levels after exercise on a bicycle ergometer in healthy euthyroid male young subjects

In order to know thyroid function during physical activity, just studied by several authors without univocal findings, we have submitted 10 young subjects, non athletes, aged 22-25 years (mean age 23, 6 +/- 1, 43) to a biologically maximal exercise on a bicycle ergometer. We have also examined the change of TSH serum levels during exercise. Our data show an evident increase of T4 (18, 60% at 10'), p less than 0.025, an increment of FT4 (28, 49 soon after the strain), and no relevant change of T3 and rT3 serum levels. Moreover TSH values show a reduction at 30' (-26, 15%) in comparison with the basal level. Our findings confirm the known increment of T4 and FT4 serum level after physical activity. It can be due, more than an hemoconcentration supported by others, to a real rise of thyroid incretion as in our opinion TSH levels reduction suggests. Concluding we think that the increase of T4 and decrease of TSH could be due to a direct influence of the physical activity on the system interested in their production.     

Exaggerated TSH responses to TRH in patients with goiter and 'normal' basal TSH levels

BACKGROUND/AIM: The availability of sensitive thyrotropin (TSH) assays decreased the diagnostic value of thyrotropin-releasing hormone stimulation tests (TRH-ST) in subclinical hypothyroidism. In this study we aimed to evaluate the relation between basal and stimulated serum TSH levels on TRH-ST and to determine the prevalence of patients with normal basal serum TSH and exaggerated TSH responses. METHODS: 179 patients (117 girls, 123 pubertal) with a median age of 12 (2.7-21.4) years who presented with goiter were enrolled and evaluated for their pubertal stage, height, thyroid autoimmunity, ultrasonography, thyroid function, and TRH-ST. Serum TSH concentrations were determined by sensitive assays. At TRH-ST, a peak serum TSH level >25 mIU/l was considered as an exaggerated response. RESULTS: 30 (17%) patients had an exaggerated TSH response. In patients with serum TSH levels between 2 and 4.68 mIU/l (upper half the normal range), an exaggerated TSH response was observed in 19.5%. A positive correlation between basal and TRH-stimulated TSH levels was determined (r = 0.536, p < 0.01). In patients with an exaggerated TSH response, 23 had normal (discordant) and 7 had high basal TSH levels (concordant). The mean basal serum TSH level was lower in the discordant group compared to the concordant group (p < 0.01). CONCLUSION: Basal serum TSH levels might not be sufficient for diagnosing subclinical hypothyroidism. Stimulated TSH levels on TRH-ST are valuable, especially when serum TSH concentrations are in the upper half of the normal range.     

Laboratory tests: level of T3, T4, TSH and antithyroid gland autoantibodies in the Polish population]

In 1986-1990 epidemiologic studies on the thyroid diseases frequency in the polish population were undertaken. During this studies the serum levels of TSH, T4, T3 and autoantibodies were estimated in more than 30 thousand people. TSH was estimated in 30749, T4 in 30928, T3 in 30621 and autoantibodies in 31265 randomly chosen people in 5 districts. We have arbitrarily established the normal range for TSH to be between 0.4-3.8 microIU/ml, for T4 4.4-12.5 micrograms% and for T3 0.9-1.95 ng/ml. The tested group has been divide in 4 subgroup: girls and boys from 1 to 15 years of age the year of the Chernobyl accident, men and women from 15 to 50 years of age at the date of the accident. TSH values in the normal range were found in 85 to 92% of the tested population, depending on the subgroup. T4 vales in the normal range were found in 85 to 92% of the tested groups. T3 vales in the normal range were found in 86 to 93% of the tested groups. The absence of any kind of autoantibodies was established in 89.7% of the tested population. TSH values was above the normal range (above 3.8 microIU/ml) in 3.4% of boys, 4.3% girls, 3.2% men and 3.8% women. TSH vales below the normal range (less the 0.4 microIU/ml) were found in 4.3% boys, 5.0% girls, 10% men and 11.2% women. T4 values above the normal range (higher then 12.5 micrograms%) were found in 12.9% boys, 12.6% girls, 4.6% men and 5.9% women.(ABSTRACT TRUNCATED AT 250 WORDS)     

双相障碍抑郁发作及单相抑郁症患者血清T3、T4、TSH和BDNF水平的相关性分析

目的:分析双相障碍抑郁发作及单相抑郁症患者与血清三碘甲状腺原氨酸(T3)、甲状腺素(T4)、甲状腺激素(TSH)和脑源性神经营养因子(BDNF)水平的相关性。方法:选取2017年12月～2019年12月我院收治的120例抑郁症患者为研究对象,按照病情不同分为双相障碍抑郁发作组(n=50)、单相抑郁症组(n=70),同时选取同期于本院进行体检的30例健康者作为对照组,检测血清T3、T4、TSH和BDNF水平,并进行汉密尔顿抑郁(HAMD)量表评分,分析血清T3、T4、TSH和BDNF水平的相关性。结果:双相障碍抑郁发作组起病年龄低于单相抑郁症组(P0.05);治疗前双相障碍抑郁发作组和单相抑郁症组血清T3水平高于对照组,TSH、BDNF水平低于对照组(P0.05),双相障碍抑郁发作组血清T4水平高于对照组,单相抑郁症组和对照组血清T4水平比较差异无统计学意义(P0.05),双相障碍抑郁发作组血清T4水平高于单相抑郁症组,TSH、BDNF水平低于单相抑郁症组(P0.05);治疗后双相障碍抑郁发作组和单相抑郁症组血清T4水平低于对照组,双相障碍抑郁发作组血清T4水平低于单相抑郁症组(P0.05),且三组血清T3、TSH、BDNF水平比较差异无统计学意义(P0.05);治疗后双相障碍抑郁发作组认知障碍因子评分低于单相抑郁症组(P0.05);Spearman相关分析显示,血清T3、T4、TSH水平和HAMD评分与BDNF呈负相关,TSH水平与BDNF呈正相关(P0.05)。结论:抑郁症患者血清T3、T4、TSH和BDNF水平存在异常,可作为判断双相障碍抑郁发作及单相抑郁症的指标。     

Free and phospholipid-bound choline concentrations in serum during pregnancy,after delivery and in newborns

The aims of this study were to determine whether serum free choline and phospholipid-bound choline concentrations change during the pregnancy or after childbirth and to determine if the serum choline concentrations of the mother and newborn are correlated. Serum free and bound choline concentrations were 10.7 +/- 0.5 microM and 2780 +/- 95 microM in control, non-pregnant women, and rose significantly (p < 0.001) to 14.5 +/- 0.6 microM and 3370 +/- 50 microM or to 16.5 +/- 0.7 microM and 3520 +/- 150 microM after 16-20 weeks or 36-40 weeks of pregnancy, respectively. Serum free and phospholipid-bound choline fell by 14-22% (p < 0.05-01) after either vaginal delivery or caesarian section, and remained low (by 15-42%; p < 0.05-0.001) for 12 h and then rose toward the baseline within 24 h. In amniotic fluid, free choline and phospholipid-bound choline concentrations were 22.8 +/- 1.0 and 19.6 +/- 0.8 microM or 24.0 +/- 1.5 and 516 +/- 43 microM at 16-20 weeks of gestational age or at term, respectively. In newborns, serum free choline concentrations were higher (p < 0.001) and phospholipid-bound choline concentrations were lower (p < 0.001) than in their mothers. These results show that serum free choline and phospholipid-bound choline concentrations are elevated during the pregnancy, which may be required for an adequate maternal supply of choline to the fetus. These observations are clinically important to determine the ideal dietary intake of choline during the pregnancy.     

Rate of recalls in congenital hypothyroidism based upon a regional survey in Isfahan, Iran, using serum T4 and TSH analyses: comparison of two different recall methods

AIMS: To evaluate and compare the recall rate in congenital hypothyroidism screening project in Isfahan, first using an approach involving measures of both TSH and T4 and then using TSH alone. METHODS: From June 2002 to January 2005, serum TSH and T4 level of referred neonates were measured at 3rd to 7th day of birth through venous sampling. If neonates' serum TSH was >20 mIU/l or T4 was <6.5 microg/dl by the first protocol, or TSH was >20 mIU/l by the second protocol, they were recalled. TSH and T4 were measured using an immunoradiometric assay and radioimmunoassay, respectively. Neonates with TSH > 10 and T4 < 6.5 on their second measurement were considered as congenitally hypothyroid. RESULTS: Serum T4 and TSH of 29,425 neonates by first and 57,235 neonates by second recall approach were measured. Recall rate was higher in the first protocol (2.2% vs. 0.6%, p < 0.05). Most of the recalled neonates in the first protocol were recalled for low T4 level (p < 0.05). The prevalence of CH was 1 in 350 livebirths. CONCLUSION: Although the recall rate was in the acceptable range by either approach, the TSH alone protocol seems to be a more sensitive and practical approach with the least recall burden and considering the high prevalence of CH in our region merit adaptation of widespread screening for CH using TSH measurements from heel stab blood spotted on filter paper.     

Serum T4, T3 and reverse T3 in ethanol fed rats.

To investigate the influence of chronic ethanol consumption on circulating thyroid hormone levels, male and female rats were given 20% ethanol as the only drinking solution daily for 8 weeks. Blood ethanol levels ranged 30–45 mg/L. In male rats serum T₄ decreased from the initial mean ± SD value of 5.2±1.4 to3.0 ±0.7 μg/dl; T₃ decreased from initial value of 97±14 to 66±11 ng/dl and rT₃ decreased from initial value of 19±9 to 10±1 ng/dl after 8 weeks of ethanol ingestion. Under similar experimental conditions, female rats showed a significant decrease in serum T₄ and rT₃ levels; however, T₃ levels decreased slightly but not significantly as compared to initial values. The results indicate adverse effect of chronic ethanol intake on serum thyroid hormone levels in rats.