Normal pituitary hormone response to thyrotrophin and gonadotrophin releasing hormones in subjects exposed to elemental mercury vapour

Exposure to elemental mercury (Hg) vapour results in an accumulation of Hg in the pituitary, the thyroid, and the testis. In this study, basal serum concentrations of pituitary hormones (thyrotrophin (TSH), prolactin (PRL), follicle stimulating hormone (FSH), and luteinising hormone (LH] or their response after administration of thyrotrophin and gonadotrophin releasing hormones did not differ between 11 male workers (mean urinary Hg (U Hg) concentration 26 nmol/mmol creatinine) and nine male dentists (U Hg concentration 1.3 nmol/mmol creatinine) exposed to elemental Hg vapour when compared with matched referent groups (U Hg concentration 0.6 and 0.4 nmol/mmol creatinine). Thus there was no evidence of an effect of Hg on the pituitary. Neither was there any association between exposure to Hg and serum concentrations of free thyroid hormones (S FT3, S FT4), testosterone, or cortisol. Increased plasma concentrations of selenium (Se) were associated with increased basal serum concentrations of TSH, decreased concentrations of basal serum cortisol, and decreased release of FSH.     

Endocrine function in mercury exposed chloralkali workers.

OBJECTIVE--The aim was to study whether functional impairment of the pituitary, thyroid, testes, and adrenal glands of humans occupationally exposed to mercury (Hg) vapour can be shown as a result of accumulation of Hg in these glands. METHODS--Basal concentrations of thyrotrophin (TSH), prolactin, free thyroxine (free T4), free 3,5,3'-triiodothyronine (free T3), antibodies against thyroperoxidase, and testosterone in serum, as well as cortisol in morning urine were measured in 41 chloralkali workers exposed (10 years on average) to Hg vapour, and in 41 age matched occupationally unexposed referents. The chloralkali workers had a mean urinary Hg concentration (U-Hg) of 15 nmol/mmol (27 micrograms/g) creatinine, and a mean blood Hg concentration (B-Hg) of 46 nmol/l. For the reference group U-Hg and B-Hg were 1.9 nmol/mmol (3.3 micrograms/g) creatinine and 17 nmol/l respectively. RESULTS--The serum free T4 concentration and the ratio free T4/free T3 were slightly, but significantly, higher in the subgroups with the highest exposure, and the serum free T3 was inversely associated with cumulative Hg exposure. This indicates a possible inhibitory effect of mercury on 5'-deiodinases, which are responsible for the conversion of T4 to the active hormone T3. Serum total testosterone, but not free testosterone, was positively correlated with cumulative Hg exposure. Prolactin, TSH and urinary cortisol concentrations were not significantly associated to exposure. CONCLUSION--Apart from inhibition of the deiodination of T4 to T3, the endocrine functions studied seem not to be affected by exposure to Hg vapour at the exposure levels of the present study. Growth hormone secretion was not studied.     

阿尔茨海默病患者甲状腺激素与皮质醇测定的临床意义及其相关性

目的:探讨阿尔茨海默病(AD)患者血清甲状腺激素与皮质醇(CORT)水平的变化以及它们的相关性。方法:采用简易精神状态量表(MMSE)对77例AD患者和100例同龄健康人进行评分,对77例AD患者和100例健康对照组进行甲状腺激素(TT3、FT3、TT4、FT4、TSH、TU)和皮质醇(CORT)的测定,并进行组间对比研究和相关性研究。结果:AD患者TT3、FT3水平明显低于健康对照组(P<0.001,P<0.001);TU、皮质醇水平明显高于健康对照组(P<0.001,P<0.01),差异有显著性。AD患者TT4、FT4水平低于健康对照组,TSH水平高于健康对照组,差别无统计学意义(P均>0.05)。AD患者血清皮质醇水平与MMSE得分呈显著负相关,与甲状腺激素水平无显著相关性;AD患者TT3水平与FT3、TT4水平呈显著正相关,TT3水平与TU水平呈显著负相关,FT3水平与TT4水平呈显著正相关,FT3水平与TU水平呈显著负相关,TT4水平与FT4水平呈显著正相关。结论:甲状腺功能异常可能与AD的发病有关,血清皮质醇水平的增高可能与AD病程的进展有关。     

肝硬化患者肝纤维化与血清甲状腺激素水平关系研究

目的 探讨肝硬化患者肝纤维化与血清甲状腺激素水平的关系.方法 纳入122例肝硬化患者,测定透明质酸(HA)、N端-Ⅲ型前胶原氨基端肽(NT-PⅢP)、IV型胶原(C-Ⅳ)及层黏连蛋白(LN)及促甲状腺素(TSH)、游离三碘甲状腺原氨酸(FT3)及游离甲状腺素(FT4)水平,分析两者的关系;同时纳入122例健康对照.结果 与健康对照相比,肝硬化患者TSH升高而FT3及FT4均下降;肝硬化患者肝纤维化程度与血清甲状腺功能呈负相关;治疗后血清甲状腺激素水平可有所升高,TSH下降.结论 肝硬化患者肝纤维化程度与血清甲状腺激素呈负相关.     

Exposure to polychlorinated biphenyls and levels of thyroid hormones in children.

As part of an epidemiologic study on exposure to a toxic waste incineration plant we investigated whether blood concentrations of polychlorinated biphenyls (PCBs), lead, and cadmium, as well as concentration of mercury in 24-hr urine samples were associated with thyroid hormone status. As an indication of status, we determined levels of thyroid-stimulating hormone (TSH), free thyroxine (FT(4)), and free triiodothyronine (FT(3)) in children living in households where [less than/equal to] 10 cigarettes were smoked per day. Eight PCB congeners (PCBs 101, 118, 138, 153, 170, 180, 183, and 187) were measured in whole blood samples. Of these, seven congeners (PCB 101 was not detected in any sample) and the sum of all PCB congeners were analyzed as predictors for thyroid hormone status in separate linear regression models adjusted for potential confounders. In addition, the possible effects of cadmium, lead, and mercury on levels of thyroid hormones were examined. Blood concentrations and information on questionnaire data were available for 320 children 7-10 years of age. We found a statistically significant positive association between the mono-ortho congener PCB 118 and TSH as well as statistically significant negative relationships of PCBs 138, 153, 180, 183, and 187 to FT(3). There was no association for the PCB congeners and FT(4). Blood cadmium concentration was associated with increasing TSH and diminishing FT(4). Blood lead and urine concentration of mercury were of no importance to thyroid hormone levels. The results stress the need for future studies on the possible influences of PCB and cadmium exposure on thyroid hormones, particularly in children. These studies should also take neurologic development into account.     

Renal and immunological effects of occupational exposure to inorganic mercury.

Seven parameters of renal dysfunction (urinary excretion of albumin, orosomucoid, beta 2-microglobulin, N-acetyl-beta-glucosaminidase (NAG), and copper; serum creatinine concentration, and relative clearance of beta 2-microglobulin) were examined in a group of chloralkali workers exposed to mercury vapour (n = 89) and in an unexposed control group (n = 75). Serum concentrations of immunoglobulins (IgA, IgG, IgM) and auto-antibodies towards glomeruli and other tissues were also determined. The parameters examined were compared between the two groups and related to different exposure parameters. In the chloralkali group median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14.3 nmol/mmol creatinine (25.4 micrograms/g creatinine). Corresponding concentrations for the control group were 15 nmol/l, 4 nmol/l, and 1.1 nmol/mmol creatinine (1.9 micrograms/g creatinine) respectively. None of the parameters of renal dysfunction differed significantly between the two groups, but there was a tendency to increased excretion of NAG in the exposed group compared with the controls. Also, a statistically significant relation existed between U-Hg and U-NAG (p less than 0.001). Serum immunoglobulin concentrations did not differ between the groups, and serum titres of autoantibodies (including antiglomerular basement membrane and antilaminin antibodies) were low in both groups. Thus the results gave no evidence of glomerular damage or of a tubular reabsorption defect at the current relatively low exposures. The findings still indicate slight, dose related tubular cell damage in the mercury exposed group. There were no signs of a mercury induced effect on the immune system.     

Renal and immunological effects of occupational exposure to inorganic mercury.

Seven parameters of renal dysfunction (urinary excretion of albumin, orosomucoid, beta 2-microglobulin, N-acetyl-beta-glucosaminidase (NAG), and copper; serum creatinine concentration, and relative clearance of beta 2-microglobulin) were examined in a group of chloralkali workers exposed to mercury vapour (n = 89) and in an unexposed control group (n = 75). Serum concentrations of immunoglobulins (IgA, IgG, IgM) and auto-antibodies towards glomeruli and other tissues were also determined. The parameters examined were compared between the two groups and related to different exposure parameters. In the chloralkali group median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14.3 nmol/mmol creatinine (25.4 micrograms/g creatinine). Corresponding concentrations for the control group were 15 nmol/l, 4 nmol/l, and 1.1 nmol/mmol creatinine (1.9 micrograms/g creatinine) respectively. None of the parameters of renal dysfunction differed significantly between the two groups, but there was a tendency to increased excretion of NAG in the exposed group compared with the controls. Also, a statistically significant relation existed between U-Hg and U-NAG (p less than 0.001). Serum immunoglobulin concentrations did not differ between the groups, and serum titres of autoantibodies (including antiglomerular basement membrane and antilaminin antibodies) were low in both groups. Thus the results gave no evidence of glomerular damage or of a tubular reabsorption defect at the current relatively low exposures. The findings still indicate slight, dose related tubular cell damage in the mercury exposed group. There were no signs of a mercury induced effect on the immune system.     

Effects of lead on the endocrine system in lead smelter workers.

In this study of the effects of lead on the endocrine system, 77 secondary lead-smelter workers (i.e., 62 active and 15 retired) were compared with 26 referents. Lead concentrations were determined in plasma with inductively coupled plasma mass spectrometry (i.e., index of recent exposure), in blood with atomic absorption spectrophotometry, and in fingerbone with K x-ray fluorescence technique (i.e., index of long-term exposure). In addition, pituitary hormones were determined in serum by fluoroimmunoassay, and thyroid hormones and testosterone in serum were determined with radioimmunoassay. Nine lead workers and 11 referents were challenged with gonadotrophin-releasing hormone and thyrotrophin-releasing hormone, followed by measurements of stimulated pituitary hormone levels in serum. Median levels of lead in plasma were 0.14 microg/dl (range = 0.04-3.7 microg/dl) in active lead workers, 0.08 microg/dl (range = 0.05-0.4 microg/dl) in retired lead workers, and 0.03 microg/dl (range = 0.02-0.04 microg/dl) in referents (1 microg/dl = 48.3 nmol/l). Corresponding blood lead concentrations were 33.2 microg/dl (range = 8.3-93.2 microg/dl), 18.6 microg/dl (range = 10.4-49.7 microg/dl), and 4.1 microg/dl (range 0.8-6.2 microg/dl), respectively. Respective bone lead levels were 21 microg/gm (range = -13 to 99 microg/gm), 55 microg/gm (range = 3-88 microg/gm), and 2 microg/gm (range = -21 to 14 microg/gm). Concentrations of basal serum hormone (i.e., free thyroid hormones, thyrotrophin, sex hormone binding globulin, and testosterone) were similar in the 3 groups. There were no significant associations between the hormones mentioned herein and blood plasma, blood lead, and bone lead levels. In the challenge test, stimulated follicle-stimulating hormone levels were significantly lower in lead workers (p = .014) than in referents, indicating an effect of lead at the pituitary level. Also, there was a tendency toward lower basal stimulated follicle-stimulating hormone concentrations in lead workers (p = .08). This effect, however, was not associated with blood plasma level, blood lead level, or bone lead level. In conclusion, a moderate exposure to lead was associated with only minor changes in the male endocrine function, particularly affecting the hypothalamic-pituitary axis. Given that sperm parameters were not studied, the authors could not draw conclusions about fertility consequences.     

Structure-function relationships of glycoprotein hormones; lessons from mutations and polymorphisms of the thyrotrophin and gonadotrophin subunit genes

The pituitary glycoprotein hormones thyrotrophin (thyroid-stimulating hormone, TSH), lutrophin (luteinising hormone, LH) and follitrophin (follicle-stimulating hormone, FSH), as well as the placental choriongonadotrophin (human chorionic gonadotrophin, hCG) are composed of a common alpha-subunit and a specific beta-subunit, coupled by noncovalent interactions. Formation of alpha/beta dimers is necessary for their biological function. Mutations and polymorphisms in the genes encoding these hormones are relatively rare, apparently because of their vital role in the regulation of reproductive and metabolic functions. However, a few genetic alterations in these genes have been identified and offer valuable, novel information about the structure-function relationships of the glycoprotein hormones. The purpose of this review is to present the known mutations and polymorphisms of the TSH, LH and FSH subunit genes and describe their functional consequences as causative factors of hypothyroidism and hypogonadism. Because genuinely inactivating TSH and gonadotrophin mutations are extremely rare, they are unlikely to be encountered in clinical practice. However, some of the polymorphisms are relatively common and because they may change the immunoreactivity of the hormone, they may result in aberrant laboratory findings.     

144例新生儿血清甲状腺激素水平与胎龄和体重的关系

目的了解新生儿血清甲状腺激素水平与胎龄和出生体重的关系。方法用化学发光免疫分析法测定144例新生儿血清T3、T4、FT3、FT4和促甲状腺激素（thyrotropin,thyroidstimulatinghormone,TSH）水平,按胎龄和出生体重分为早产儿组、足月儿组、低出生体重儿组和正常体重儿组并进行组间比较,并对胎龄、出生体重与甲状腺激素水平行相关性分析。结果早产儿组T3水平1.41±0.41 nmol/L,显著低于足月儿组1.69±0.49 nmol/L（t=3.32,P=0.001）,胎龄与T3水平明显相关（r=0.31,P〈0.01）,而T4、FT3、FT4和TSH水平在早产儿和足月儿无显著性差异;低出生体重儿T3（t=2.74,P=0.007）和T4（t=2.12,P=0.04）水平显著低于2 500 g以上者,出生体重与T3（r=0.34,P〈0.01）和T4（t=0.24,P〈0.01）明显相关。结论新生儿T3、T4水平与胎龄及出生体重有关,早产儿、低出生体重儿甲状腺功能明显低于足月儿和正常出生体重儿。     

镉接触工人体内血清性激素水平的变化

目的 探讨镉接触工人体内血清性激素水平的变化及其机制。方法 选取南方某冶炼厂镉接触工人及当地健康男性为调查对象,经空气采样测定各车间空气中镉的浓度,用原子吸收分光光度法测定尿镉,并经肌酐校正作为调查对象体内镉负荷的生物标记物;同时测定工人体内性激素水平,并进行镉接触的剂量－效应评定。结果 在控制年龄等混杂因素后,血清睾酮水平随镉接触水平的增高而呈升高趋势,其中尿镉为10．9－21．9μmol/mol肌酐及＞21．9μmol/mol肌酐组的睾酮水平分别为：13．00nmol／L和11．37nmol／L,与0．0－2．2μmol/mol肌酐组的9．31nmol／L比较,差异有显著性;电解车间及尿镉＞21．9μmol/mol肌酐组人的血清黄体生成素水平分别为4．11U／T和4．32U／L,显著同于对照组的2．52U／L和尿镉0．0－2．2μmol/mol肌酐组的2．64U／L。结论 镉接触能引起工人血清性激素水平的变化。     

西安地区孕妇妊娠期甲状腺功能指标参考区间的研究

为建立西安地区孕妇妊娠早期(T1期)、中期(T2期)、晚期(T3期)甲状腺功能指标的参考区间。本研究采用横断面研究的方法,通过调查问卷共招募表观健康的620名孕妇,采用全自动化学发光分析仪检测血清促甲状腺激素(TSH)、总三碘甲状腺原氨酸(TT3)、总甲状腺激素(TT4)、游离三碘甲状腺原氨酸(FT3)和游离甲状腺激素(FT4)水平,并且使用新一代TSH检测试剂(3rd IS),以探讨妊娠期特异性甲状腺功能指标的参考区间。结果显示,T1期、T2期和T3期TSH的参考区间分别是0.05-4.59 mIU/L、0.61-6.01 mIU/L、0.63-4.78 mIU/L;TT3是1.62-2.97 nmol/L、1.59-2.95 nmol/L、1.45-2.70 nmol/L;TT4是95.49-185.00 nmol/L、92.70-181.54 nmol/L、77.93-155.09 nmol/L;FT3是3.18-5.22 pmol/L、2.78-4.67 pmol/L、2.51-4.18 pmol/L;FT4是7.72-12.97 pmol/L、6.90-11.09 pmol/L、5.63-9.85 pmol/L。所有甲状腺功能指标在不同孕期之间差异均有统计学意义(TSH: H=30.879, P<0.01;FT3: H =153.827, P<0.01;FT4:H =229.967, P<0.01;TT3: H =36.484, P<0.01;TT4: H =58.531, P<0.01)。分别收集20例独立样本对妊娠3个期的TSH、FT3、FT4、TT3、TT4的参考区间进行验证,全部验证通过。     

Thyroid Hormones in Relation to Lead,Mercury, and Cadmium Exposure in the National Health and Nutrition Examination Survey, 2007–2008

Background: Heavy metals, such as lead (Pb), mercury (Hg), and cadmium (Cd), are known toxicants, but their associations with the thyroid axis have not been well quantified at U.S. background levels.Objectives: We investigated the relationships between thyroid hormones (total and free thyroxine [TT₄ and FT₄], total and free triiodothyronine [TT₃ and FT₃], thyroid-stimulating hormone [TSH], and thyroglobulin [Tg]) and levels of Pb, Hg, and Cd in blood and Cd in urine.Methods: We separately analyzed a sample of 1,109 adolescents (12–19 years of age) and a sample of 4,409 adults from the U.S. National Health and Nutrition Examination Survey (NHANES) 2007–2008. We estimated associations after adjusting for age, sex, race, urinary iodine, body mass index, and serum cotinine.Results: The geometric mean (GM) levels of blood Pb (BPb), total Hg, and Cd were 0.81 µg/dL, 0.47 µg/L, and 0.21 µg/L in adolescents and 1.43 µg/dL, 0.96 µg/L, and 0.38 µg/L in adults, respectively. The GMs of urinary Cd were 0.07 and 0.25 µg/g creatinine in adolescents and adults, respectively. No consistent pattern of metal and thyroid hormone associations was observed in adolescents. In adults, blood Hg was inversely related to TT₄, TT₃, and FT₃ and urinary Cd was positively associated with TT₄, TT₃, FT₃, and Tg, but there were no associations with Pb. Associations were relatively weak at an individual level, with about 1–4% change in thyroid hormones per interquartile range increase in Hg or Cd.Conclusions: Our analysis suggests an inverse association between Hg exposure and thyroid hormones, and a positive association between Cd exposure and thyroid hormones in adults.     

Mercury and selenium in workers previously exposed to mercury vapour at a chloralkali plant.

The concentrations of total mercury (B-Hg), inorganic mercury (B-IHg), and methyl mercury (B-MeHg) in whole blood, urinary mercury (U-Hg), and selenium in urine (U-Se) and whole blood (B-Se) were determined in 74 chloralkali workers previously exposed to Hg vapour, and compared with 51 age matched referents. Dental amalgam state, fish consumption, and exposure related indices were studied with regard to the determined elements. A significant relation between the surface of dental amalgam and U-Hg (Pearson's r = 0.63, p < 0.001) was found among the referents. Mean U-Se was significantly lower (p < 0.001) among the subjects previously exposed to Hg (34.1 nmol/mmol creatinine) compared with that for the referents (42.6 nmol/mmol creatinine). A significant negative relation between the cumulative Hg dose and U-Se was also found. The mechanisms and the clinical significance of these findings are not clear. No relation between current U-Hg and previous occupational exposure to Hg was found among subjects in whom exposure had ceased more than one year before the study.     

Gender differences in the effects of organochlorines, mercury, and lead on thyroid hormone levels in lakeside communities of Quebec (Canada)

Environmental chemicals can disrupt endocrine balance and in particular thyroid hormone (TH) homeostasis. However, studies differ with respect to thyroid profile changes and gender differences are rarely examined. This study investigated the THs, triodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH), in relation to serum organochlorines (OCs), bioindicators of mercury (Hg) and blood lead (Pb) in 211 freshwater fish consumers (124 men and 87 women) from two communities in Canada. Thyroid hormones were within the normal range and the bioindicators of exposure were low compared to other reports on fish consumers. Stratified analysis showed that for women, serum T3 concentrations were negatively related to serum concentrations of PCB 138, PCB 153, the non-coplanar congeners, Arochlor 1260, and ΣPCB, as well as p,p′-DDE. No relations were observed between T4 and any of the chemicals measured, but TSH was negatively related to blood Pb. For men, serum T4 was inversely related to PCB 138, non-ortho-substituted (dioxin-like) PCBs and ΣPCB. A significant positive relationship was observed between serum TSH and different PCB congeners (PCB 138, PCB 180, non-coplanar congeners, mono-ortho coplanar congeners, dioxin-like PCBs), as well as ΣPCB. Serum TSH increased with hair and blood Hg concentrations and was highest among those in the highest 50th percentile for both Hg and dioxin-like PCB congeners compared to the others. No associations were observed for T3 in men. These findings suggest that even at low concentrations, these environmental contaminants can interfere with thyroid status and effects may differ by gender.     

不同孕期和年龄孕妇甲状腺功能指标的比较研究

目的：研究妊娠早中晚期不同年龄孕妇甲状腺功能指标的变化。方法测定温州地区1839名不同孕期的孕妇血清三碘甲状腺原氨酸（FT3）、游离甲状腺激素（FT4）、总三碘甲状腺原氨酸（TT3）、总甲状腺素（TT4）、促甲状腺激素（TSH）、抗甲状腺球蛋白抗体（TGAb）及抗甲状腺过氧化物酶抗体（TPOAb）。结果妊娠早中晚期3组孕妇的FT3、FT4、TT3、TT4、TSH中位数比较,除TT4在妊娠早期与中期差异均无统计学意义（P＞0.05）外,其余各项指标在妊娠早中晚期之间的差异均有统计学意义（P＜0.05）;FT3和FT4的中位数随孕期逐渐降低,TSH中位数随孕期逐渐升高,TT3中位数在孕中期最高（1.47 nmol/L）,TT4中位数晚期最低（80.67 nmol/L）。按年龄分组,＞30岁组在妊娠早中晚3期的TSH值均低于≤30岁组（P＜0.05）;妊娠中期的FT4、TT3、TT4和妊娠晚期的FT3值均低于≤30岁组（P＜0.05）。TGAb 和TPOAb 的阳性率妊娠晚期分别为4.74％和1.63％,均低于妊娠早期的阳性率（14.40％和5.56％）和妊娠中期的阳性率（11.20％和3.08％）,差异均有统计学意义（P＜0.05）。结论不同孕期孕妇的甲状腺功能指标存在明显差异,不同年龄段孕妇的甲状腺功能指标亦存在差异,应加强孕期甲状腺功能监测,重视正常参考值范围的研究。     

Effects of zinc deficiency upon pituitary function in sexually mature and immature male rats.

Serum pituitary levels of growth hormone (GH), thyrotropin (TSH), prolactin (PRL), luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured in sexually mature (adult) and sexually immature (juvenile) male rats who had been deprived of dietary zinc for 15 and 7 weeks, respectively. When compared to pair-fed control rats receiving a zinc supplemented diet, both the adult and juvenile zinc deficient rats had significantly lower body weights, tail lengths and ventral prostate weights. The testes of the sexually immature rats were also smaller than those of the pair-fed animals. In sexually mature, zinc deficient rats serum concentrations of GH and testosterone were significantly lower and serum LH levels significantly higher than in ad libitum fed control rats. Pituitary and hypothalamic levels of other hormones did not differ from values recorded in control animals. In sexually immature zinc deficient rats serum concentrations of GH were also significantly depressed; pituitary content and concentration of LH and pituitary and serum levels of FSH were significantly increased over control values. No discernible effects of zinc deficiency upon hyplthalamic content of LH-releasing hormone or serum concentrations of PRL or TSH were recorded in juvenile rats. Zinc deficiency has minimal effects upon the hypothalamic-pituitary axis of sexually mature rats. In sexually immature males, zinc deprivation leads to impairment of gonadal growth and increased synthesis and/or secretion of the pituitary gonadotropins.     

Iron deficiency anaemia in childhood and thyroid function

Studies in animals and adults have indicated iron deficiency anaemia to be associated with altered thyroid hormone metabolism. The aim of the present study was to determine the effect of iron deficiency anaemia on the thyroid function of young children. Concentrations of thyroxine (T4) and triiodothyronine (T3), free thyroid hormones (fT4 and fT3), thyroxine binding globulin (TBG), and thyroid stimulating hormone (TSH) were measured in the basal state and in response to an intravenous bolus of thyrotropin releasing hormone (TRH) in nine children one to three years of age with iron deficiency anaemia (IDA) before and after treatment with oral iron. The results of the anaemic children were also compared to basal and stimulated concentrations of thyroid hormones, TBG, and TSH of eight iron sufficient, age-matched children. Seven of the IDA and 6 of the control children were male. The mean haemoglobin (Hb) and serum ferritin (SF) in the IDA children at baseline were 93g/L (range 81-102) and 6g/L (range 1-12) which increased to 121g/L (range 114-129) and 54g/L (range 19-175), respectively, after a mean of 2.3 months (SD 0.5) of iron therapy. In the control group, mean Hb and SF were 125g/L (range 114-130) and 51 g/L (range 24-144), respectively. The basal values of TBG and thyroid hormones of the IDA children before and after iron treatment were not different from the control children. Similarly, there was no statistical difference in the thyroid hormones in the IDA children before compared to after resolution of the anaemia. Compared to the control children, the TSH response over time to TRH, TSH area under the curve (TSHAUC), and the peak TSH value after stimulation were all lower in the IDA children both before and after resolution of anaemia, but the differences were not significant. Iron therapy and resolution of anaemia had no effect among the IDA children. The time to reach the peak TSH concentration was longer in the IDA children (P=0.08) than the control children before iron therapy. While the time to peak TSH decreased upon resolution of the anaemia, the difference was not significant. There was no effect of Hb concentration, age, or anthropometry with TSH, TSHAUC, or time to peak TSH after TRH stimulation in the IDA children before treatment. Normal thyroid function was preserved in these children with iron deficiency anaemia, however three of nine children had minor abnormalities of hypothalamic-pituitary function. These results indicate that hypothyroidism is unlikely to be a major cause of impaired psychomotor development or growth in young children with iron deficiency anaemia.     

Effects of Lead on the Endocrine System in Lead Smelter Workers

In this study of the effects of lead on the endocrine system, 77 secondary lead-smelter workers (i.e., 62 active and 15 retired) were compared with 26 referents. Lead concentrations were determined in plasma with inductively coupled plasma mass spectrometry (i.e., index of recent exposure), in blood with atomic absorption spectrophotometry and in fingerbone with K x-ray fluorescence technique (i.e., index of long-term exposure). In addition, pituitary hormones were determined in serum by fluoroimmunoassay and thyroid hormones and testosterone in serum were determined with radioimmunoassay. Nine lead workers and 11 referents were challenged with gonadotrophin-releasing hormone and thyrotrophin-releasing hormone, followed by measurements of stimulated pituitary hormone levels in serum. Median levels of lead in plasma were 0.14 μg/dl (range = 0.04–3.7 μg/dl) in active lead workers, 0.08 μg/dl (range = 0.05–0.4 μg/dl) in retired lead workers and 0.03 μg/dl (range = 0.02–0.04 μg/dl) in referents (1 μg/dl = 48.3 nmol/l). Corresponding blood lead concentrations were 33.2 μg/dl (range = 8.3–93.2 μg/dl), 18.6 μg/dl (range = 10.4–49.7 μg/dl) and 4.1 μg/dl (range 0.8–6.2 μg/dl), respectively. Respective bone lead levels were 21 μg/gm (range = -13 to 99 μg/gm), 55 μg/gm (range = 3–88 μg/gm) and 2 μg/gm (range = -21 to 14 μg/gm). Concentrations of basal serum hormone (i.e., free thyroid hormones, thyrotrophin, sex hormone binding globulin and testosterone) were similar in the 3 groups. There were no significant associations between the hormones mentioned herein and blood plasma, blood lead and bone lead levels. In the challenge test, stimulated follicle-stimulating hormone levels were significantly lower in lead workers (p = .014) than in referents, indicating an effect of lead at the pituitary level. Also, there was a tendency toward lower basal stimulated follicle-stimulating hormone concentrations in lead workers (p = .08). This effect, however, was not associated with blood plasma level, blood lead level, or bone lead level. In conclusion, a moderate exposure to lead was associated with only minor changes in the male endocrine function, particularly affecting the hypothalamic-pituitary axis. Given that sperm parameters were not studied, the authors could not draw conclusions about fertility consequences.     

早产儿甲状腺激素浓度变化与疾病危重程度相关性的研究

目的 研究早产儿血清甲状腺激素浓度变化与疾病危重程度的相关性,为早期筛查危重早产儿提供依据.方法 选取江西省儿童医院2018年3月-2019年6月收取的209名早产儿为研究对象,按疾病危重程度分为危重组(n=23)、危重转归组(n = 60)、非危重组(n=126).抽取早产儿出生后第7、14天静脉血检测FT3、FT4...