不同Wagner分级糖尿病足与甲状腺功能的临床研究

目的对不同Wagner分级的糖尿病足病(DF)患者甲状腺功能进行临床分析,并与无足病的2型糖尿病患者(NDF)比较,分析甲状腺功能与足病严重程度的关系。方法回顾性地分析解放军第306医院2009年6月至2015年6月收治的481例DF患者及445例NDF患者。按照Wagner分级标准,将DF患者分为4组,分别为Wagner1、2、3及(4~5)组,分析各组间甲状腺功能状态。采用SPSS21.0进行统计学分析。结果与NDF组患者相比,DF组甲状腺功能异常的患病率增高(17.67%vs 12.36%,χ~2=5.082,P0.05),NDF组和DF组均以亚临床甲减、甲状腺功能正常病态综合征(ESS)为主(6.07%,8.73%);NDF组与DF组的总三碘甲状腺原氨酸(TT3)、总甲状腺素(TT4)、游离三碘甲状腺原氨酸(FT3)之间差异有统计学意义(P0.01),随着Wagner分级水平增高,DF组的TT3、FT3值降低,差异有统计学意义(P0.01);DF组ESS比例随着Wagner分级水平升高而升高(2%,2.55%,9.24%,18.33%,t=24.455,P0.05);伴ESS的糖尿病患者住院时间较长;logistic回归分析发现性别、住院时间、超敏C反应蛋白、TT4(OR=2.938,1.178,1.222,1.047,P0.01)是DF的独立危险因素,而白蛋白、餐后2 h血糖、FT3是DF的保护因素(OR=0.881,0.899,0.406,P0.01)。结论 DF患者ESS患病率高,而且Wagner≥3级患者的患病率显著增加,甲状腺功能检测有助于评价DF患者的临床病情及判断愈后。     

糖尿病酮症酸中毒患者甲状腺功能状态分析

目的 分析糖尿病酮症酸中毒(DKA)患者甲状腺功能(甲功)状态.方法 选择广西医科大学第九附属医院2005年11月至2013年12月住院DKA患者93例,并按性别、年龄(≤30岁组、30 ～ 60岁组、≥60岁组)、糖尿病分型(1型糖尿病、2型糖尿病)进行分组,测定各组血清FT3、FT4、促甲状腺激素(TSH)水平,并进行比较.结果 甲功正常的病态综合征(ESS)发生率为79.6％(74/93),甲功正常为9.7％ (9/93),甲状腺功能亢进症发生率为7.5％ (7/93),亚临床甲状腺功能亢进症发生率为2.2％ (2/93),甲状腺功能减退症发生率为1.1％ (1/93).男性组DKA患者的FT3水平低于女性组(t=-2.046,P=0.044),FT4、TSH比较差异无统计学意义;1型糖尿病组FT4水平低于2型糖尿病组(t-2.352,P=0.021),但TSH高于2型糖尿病组(t=2.454,P=0.016),FT3比较差异无统计学意义(P＞0.05).1型糖尿病组低T3/T4综合征比例高于2型糖尿病组(x2 =4.443,P =0.035).低T3综合征比例随着年龄增加有增加的趋势(x2=7.081,P=0.029);低T3/T4综合征比例随着酸中毒严重程度的增加有增加的趋势(x2=6.759,P=0.034).结论 DKA患者甲功异常发生率较高,甲功异常表现形式多样,ESS最常见.     

促甲状腺激素受体抗体（TRAb）检测在甲状腺疾病鉴别诊断中的应用

目的分析血清促甲状腺激素受体抗体（TRAb）测定在甲状腺疾病临床诊断中的应用价值。方法采用放射受体分析和放射免疫分析法,测定373例甲状腺疾病患者血清TRAb和T3、T4、TSH、FT3、FT4含量,并根据以上参数的含量为标准,把患者分为单纯性甲状腺肿组、桥本氏病组、原发性甲减组、甲状腺功能亢进（甲亢）组、药物性甲减组,以45例非甲状腺疾病血清中TRAb和T3、T4、TSH、FT3、FT4含量作为对照组。结果单纯性甲状腺肿组、桥本氏病组血清TRAb含量与正常对照组无差异（χ^2=0.462,P〉0.05）;甲亢组、原发性甲减组血清TRAb含量明显高于正常对照组（χ^2=17.035,P〈0.01）;药物性甲减组血清TRAb含量与甲亢组差异显著（χ^2=4.804,P〈0.05）,与正常组比较亦有显著性差异（χ^2=9.071,P〈0.05）;血清TRAb含量与各组间T3、T4、FT3、FT4及TSH浓度之间无显著相关性（χ^2=0.325,P〉0.05）。结论血清TRAb含量的监测对甲状腺疾病的诊断、鉴别诊断、疗效观察等具有临床应用价值。     

不同孕期孕妇甲状腺功能相关指标分析

目的 探讨不同孕期孕妇甲状腺激素水平变化及其与抗甲状腺过氧化物酶抗体(TPOAb)之间的关系.方法 377例不同孕期的孕妇,采用固相化学发光酶免疫分析法( ICMA)测定血清促甲状腺激素(TSH)、游离甲状腺激素(FT4)、游离三碘甲状腺原氨酸(FT3)、总甲状腺素(TT4)、总三碘甲状腺原氨酸(TT3)、TPOAb.结果 正常组孕妇早、中、晚期TSH中位数依次上升(均P＜0.05).TPOAb阳性组TSH中位数高于TPOAb阴性组(P＜0.05),TPOAb阳性组中临床和亚临床甲状腺功能减退症(甲减)的患病率高于TPOAb阴性组(P＜0.05).采用FT4及TT4诊断法诊断亚临床甲减患病率分别为18.04％及23.61％;采用TT4及FT4诊断临床甲减的患病率分别为0.27％及5.84％( P＜0.05).结论 应当重视FT4和TT4在妊娠中晚期甲减诊断的差异;应建立孕期正常的甲状腺激素切点值并开展TPOAb的筛查.     

2型糖尿病患者甲状腺功能的状态及其临床意义

目的 探讨2型糖尿病患者血清甲状腺激素水平的变化及其临床意义.方法 选择179例住院2型糖尿病患者,根据病情将其分为单纯血糖升高组（A组）58例,急性代谢紊乱组（B组）55例,严重合并症组（C组）66例,设正常对照组34例.所有患者入院后检测血清TT3、TT4、FT3、FT4、TSH,同时检测血糖、C肽和血脂水平.治疗后死亡18例,存活161例,存活者于出院前复查甲状腺激素水平.结果 女性患者的TSH水平显著高于男性（P〈0.01）,FT3,和FT4水平则低于男性（P〈0.05）;存活者治疗后各组TT3、FT3较治疗前有明显升高（P〈0.05或P〈0.01）,C组TSH治疗后有所下降（P〈0.05）;死亡者治疗前TT3、FT3水平明显低于存活者（P〈0.01）;相关分析显示,随着糖尿病患者FBG和HbAlc的升高,FT3、TSH呈下降趋势.结论 2型糖尿病患者甲状腺功能状态与血糖、年龄、性别、病程和疾病严重程度有关;监测血清甲状腺激素水平可作为2型糖尿病病情严重程度及估计预后的一项参考指标.     

2型糖尿病患者尿微量白蛋白与血清甲状腺激素的相关性研究

选取2型糖尿病患者105例,分为糖尿病微量蛋白尿组及糖尿病正常蛋白尿组,设对照组30例,检测血清游离T3(FT3)、游离T4(FT4)、促甲状腺素(TSH)、甲状腺素(T4)、三碘甲状腺原氨酸(T3)、尿微量白蛋白等指标,分析2型糖尿病患者尿微量白蛋白与血清甲状腺激素之间的相关性。结果三组之间FT3、T3、尿微量白蛋、HbA1c的差异有统计学意义(P<0.05),进一步两两比较,DM微量白蛋白尿组的FT3、T3显著低于DM正常蛋白尿组及对照组,尿微量白蛋白、HbA1c显著高于DM正常蛋白尿组及对照组,差异有统计学意义(P<0.05);尿微量白蛋白、FT3与病程有关,随病程的延长,尿微量白蛋白逐渐升高,FT3则逐渐降低,尿微量白蛋白与FT3呈负相关,相关系数为-0.496(P<0.05)。结论糖尿病伴有微量白蛋白尿患者会出现FT3、T3降低,尿微量白蛋白与FT3呈负相关,检测这两项指标对诊断、治疗及评估预后有重要意义。     

住院2型糖尿病患者甲状腺功能状态的分析

目的分析2型糖尿病患者甲状腺功能状态。方法检测120例住院2型糖尿病患者血清游离T3（FT3）、游离T4（FT4）、促甲状腺激素（TSH），设正常对照组48例。结果2型糖尿病患者TSH水平显著高于正常对照组（P=0．000），FT3水平显著低于正常对照组（P=0．038）。2型糖尿病患者甲状腺功能异常者占40％，其中16．67％呈功能亢进，23．33％呈功能减退，其中女性2型糖尿病患者亚临床甲状腺功能减退达14．80％，显著高于男性（OR=5．565，95％CI：1．129～27．431）。男性2型糖尿病患者甲状腺功能减退的年龄显著高于功能亢进者（P=0．030），糖尿病病程有延长趋势（P=0．079）。而不同甲状腺功能状态的女性2型糖尿病患者的年龄、糖尿病病程无统计学差异。结论2型糖尿病患者甲状腺功能异常的发生率高，其中女性2型糖尿病患者亚临床甲状腺功能减退的患病率更高。     

糖尿病血清甲状腺激素水平的变化及其临床意义

对糖尿病患者171例、正常健康成人30例,采用放射免疫分析法测定其甲状腺激素水平.结果糖尿病患者血清总T3(TT3)、总T4(TT4)、游离T3(FT3)、游离T4(FT4)水平均显著低于正常对照组(P值均＜0.01),血清TSH水平无明显变化,rT3水平显著升高,(P＜0.05).结论糖尿病患者血清TH水平下降,rT3升高,TSH无变化对其甲状腺功能的评价具有重要意义.     

亚临床甲状腺功能减退与2型糖尿病慢性并发症的关系

目的探讨亚临床甲状腺功能减退(SCH)与T2DM慢性并发症的关系。方法将1294例T2DM患者分为SCH组和甲状腺功能正常组,比较两组间慢性并发症患病率及患者的甲状腺功能,采用Logistic多元回归分析SCH与T2DM慢性并发症的关系。结果 18.8%的T2DM患者合并SCH。SCH组糖尿病慢性肾脏疾病(CKD)、DR、糖尿病周围神经病变(DPN)和糖尿病足(DF)患病率均高于甲状腺功能正常组(P0.05)。CKD、DR和DPN患者FT3下降,促甲状腺激素(TSH)升高(P0.05)。Logistic多元回归分析显示,SCH为CKD的独立危险因素(OR=3.39,P=0.012)。结论 T2DM合并SCH患者CKD、DR、DPN和DF患病率升高。SCH是CKD的独立危险因素。     

850例老年男性甲状腺结节与甲状腺功能调查

目的 调查男性老年人甲状腺结节的患病情况及甲状腺功能.方法 对850例参加2010年度本院干部体检老年男性进行甲状腺功能检查和甲状腺高频超声检查.按照有无甲状腺结节进行分组,进行结节与甲状腺功能的相关性分析.结果 850例体检对象中甲状腺结节患病率为71％,结节患病率随着年龄增加而明显升高(P＜0.05).甲状腺结节组除甲状腺前后径线较正常组增长外(P＜0.05),余各径线测定值和甲状腺功能与正常组相比差异无统计学意义.入选对象的血清TT3、FT3水平随年龄增长而降低(P＜0.05),TT4、FT4和促甲状腺激素水平无增龄性改变.结论 老年男性人群具有较高的甲状腺结节患病率.早期较小的结节对甲状腺功能无显著影响.老年男性的TT3、FT3水平随年龄增长而降低.     

Minor alterations in thyroid-function tests associated with diabetes mellitus and obesity in outpatients without known thyroid illness

Thyroid function tests might be affected by diabetes and obesity. To evaluate the influence of these parameters in routine conditions, 72 diabetic and 53 non-diabetic outpatients without known thyroid diseases or severe chronic illness were recruited over a 7-month period. For each patient, dosages of thyrotropin (TSH), total and free thyroxine (TT4 and FT4, respectively), total and free triiodothyronine (TT3 and FT3) and T3 resin uptake (T3RU) were performed by radioimmunoassays. The simultaneous influence of various parameters known to affect thyroid-function tests was evaluated by multivariate linear regression. The studied variables included gender, age, glucosteroids, estrogens, tobacco habits, iodine contacts, body mass index (BMI) and diabetes mellitus. Tobacco habits and iodine contacts did not influence any tests. As expected, estrogens induced an increase in TT4 and TT3 values (p < 0.001 and 0.020, respectively) associated with a decrease in T3RU (p < 0.001). Consequently, females had lower T3RU than males (p < 0.0001). Corticotherapy was associated with decreased TSH values (p = 0.022). TT3 and FT3 decreased with age (p < 0.001), whereas T3RU and FT4 increased (p = 0.020 and 0.004, respectively). In contrast to an increase in TSH (p = 0.006), TT4 and FT4 decreased at higher BMI levels (p = 0.018 and 0.004, respectively), which is consistent with subclinical hypothyroidism. In diabetic patients, TSH was lower than in nondiabetic subjects (p = 0.039). Thus, the present study indicates that besides known parameters such as age and drugs, thyroid-function tests can also be altered by diabetes mellitus and obesity.     

成人1型糖尿病患者甲状腺功能与糖脂代谢的关系研究

探讨成人1型糖尿病(T1DM)患者甲状腺功能与糖脂代谢指标的关系。回顾性分析2008年1月至2020年1月在山东大学附属省立医院内分泌科住院的230例T1DM患者资料,结果显示,成人T1DM患者的促甲状腺激素(TSH)与总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白-胆固醇(LDL-C)水平呈正相关(r值分别为0.239、0.166、0.249,P值均<0.05)。游离三碘甲状腺原氨酸(FT 3)与空腹血糖(FPG)、糖化血红蛋白(HbA1c)、TC和LDL-C呈负相关(r值分别为-0.272、-0.240、-0.197、-0.220,P值均<0.005)。游离甲状腺素(FT₄)与TC、LDL-C呈负相关(r值分别为-0.171、-0.170,P值均<0.05)。TC是TSH、FT₃、FT₄的独立预测因子,FT₃、FT₄是HbA1c的独立预测因子,TSH是TC、TG、LDL-C的独立预测因子。成人T1DM患者甲状腺功能与糖脂代谢密切相关,有必要常规检测T1DM患者的甲状腺功能。     

高血压脑出血甲状腺功能异常患者再出血及预后的观察

目的 探讨高血压脑出血(HICH)甲状腺功能异常患者再出血的发生与预后情况.方法 纳入盐城市亭湖区人民医院2014年5月至2019年5月收治的HICH甲状腺功能异常患者80例.根据患者是否发生再出血,分成再出血组14例、未再出血组66例.比较两组甲状腺功能指标,包括促甲状腺激素(TSH)、总甲状腺素(TT4)、总三碘甲...     

健康高龄老年人甲状腺激素水平变化趋势分析

目的 探讨80岁以上高龄老年人甲状腺激素水平变化趋势.方法 将602例健康志愿者按年龄分为中青年组(20～59岁)226例、老年组(60～79岁)195例和高龄组(80～102岁)181例,采用化学发光法及放射免疫法测定志愿者血清三碘甲状腺原氨酸(TT3)、甲状腺素(TT4)、游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺激素(TSH)、反T3(rT3)水平,并以SPSS 13.0进行统计分析.结果 老年组与中青年组比较,血清FT3和TT3降低,差异有统计学意义(t值分别为2.793和3.627,均为P＜0.01);高龄组与中青年组比较,TT3、TT4、FT3、TSH、rT3浓度差异有统计学意义(t值分别为10.930、6.065、15.398、-2.933、-5.643,均为P＜0.01);老年组与高龄组比较,TT3、TT4、FT3、TSH、rT3浓度差异有统计学意义(t值分别为8.382、4.298、11.573、-3.383、-5.148,均为P＜0.01).FT3、TT3、TT4浓度与年龄呈负相关(r值分别为-0.51、-0.39、-0.25,P＜0.01),rT3、TSH浓度与年龄呈正相关(r值分别为0.32、0.12,P＜0.01),FT4与年龄无相关.高龄组高于或低于临床正常参考值范围的阳性发生率,在TT3、TT4、FT3、FT4、TSH、rT3中分别为0、0、13.8%、0、6.6%、21%.结论 随着年龄增长,老年人血清甲状腺激素水平及促甲状腺激素均有改变,特别是80岁及以上高龄老年人,血清FT3、rT3、TSH变化更为明显,建议临床设立老年人不同年龄段的血清甲状腺激素正常参考值范围,以减少假阳性的发生率.

Abstract：

Objective To explore the variation tendency of serum thyroid hormone level in the elderly aged over 80 years.Methods The 602 healthy volunteers were divided into 3 groups by age:young group (20-59 years of age,n= 226),elderly group (60-79 years of age,n= 195),and advanced age group (80-102 years of age,n=181).Fasting blood of all persons was harvested,then the levels of serum total triiodothyroxine (TT3),total thyroxine (TT4),free tri-iodothyronine (FT3),free thyroxine (FT4),thyroid-stimulating hormone (TSH) and reverse tri-iodothyronine (rT3) were determined by chemistry luminescence technique and radioimmunoassay.Statistical analysis was made by the software SPSS 13.0.Results The levels of serum FT3 and TT3 were lower in elderly group than in young group (t=2.793,3.627,P=0.005,0.000).There were significant differences in the levels of serum TT3,TT4,FT3,TSH and rT3 between young group and advanced-age group (t =10.930,6.065,15.398,- 2.933,- 5.643,all P = 0.000),also between elderly group and advanced-age group (t= 8.382,4.298,11.573,-3.383,-5.148,all P＜0.001).The levels of serum FT3,TT3 and TT4 were negatively correlated with age (r=- 0.51,-0.39 and -0.25,respectively,all P＜0.01).And the levels of serum rT3 and TSH showed positive relationships with age (r=0.32,0.12,all P＜0.01).There were no relationships between the level of serum FT4 and age.The positive rate of serum TT3,TT4,FT3,FT4,TSH and rT3 concentration beyond the reference value was 0,0,13.8%,0,6.6% and 21% in advanced-age group,respectively.Conclusions The levels of serum thyroid hormone and thyroid-stimulating hormone change with age.The levels of FT3,rT3 and TSH change obviously in the elderly aged over 80 years.It could reduce the false positive rate in clinical practice if normal reference range for serum thyroid hormone levels in different aged elderly is established.     

二甲双胍对糖尿病患者血清促甲状腺激素水平的影响

目的探讨二甲双胍对未服用甲状腺激素的糖尿病患者血清甲状腺激素和促甲状腺激素水平的影响。方法测定未服用甲状腺激素的糖尿病患者的血清游离三碘甲腺原氨酸（FT3）、游离甲状腺素（FT4）、总三碘甲腺原氨酸（TT3）、总甲状腺素（TT4）和促甲状腺激素（TSH）的水平，并分析其与是否服用二甲双胍的关系。结果未服用二甲双胍组与服用二甲双胍组的血清FT3（4.65±0.68vs4.59±0.67pmol/L）、FT4（17.88±3.26vs17.75±2.85pmol/L）、TT3（1.79±0.42vs1.77±0.38nmol/L）、TT4（107.9±22.1vs109.2±22.1nmol/L）和lnTSH（0.49±0.83vs0.47±0.87mU/L）之间的差异无统计学意义（P〉0.05）。结论未服用甲状腺激素的糖尿病患者在服用二甲双胍期间促甲状腺激素的水平不受影响。     

Effects of severity of chronic obstructive pulmonary disease on thyroid function

To investigate thyroid function in chronic obstructive pulmonary disease (COPD), 46 consecutive patients (35 men) with stable, mild-to-severe disease, having a mean (SD) age of 67 +/- 7 years were studied. All subjects underwent pulmonary function tests (PFTs), arterial blood gas determination, and measurement of serum total thyroxine (TT4), total triiodothyronine (TT3), resin T3 uptake (RT3U), reverse triiodothyronine (rT3), and thyroid-stimulating hormone (TSH) levels. The free thyroxine and free triiodothyronine indexes (FT4I = RT3U/30TT4 and FT3I = RT3U/30TT3, respectively) along with the TT3/TT4 ratio were calculated; the latter was used as a marker of peripheral conversion of thyroxine into triiodothyronine. Interleukin (IL)-6 was also measured to evaluate its potential associations with thyroidal hormone levels. On the basis of forced expiratory volume in 1 second (FEV1), patients were divided in 2 groups: group 1, (FEV1 > or = 50% of predicted, n = 26), with mild-to-moderate COPD and group 2 (FEV1 < 50% of predicted, n = 20) having severe disease. All subjects had normal serum thyroid hormone levels; for the entire COPD population, mean values were 7.80 +/- 1.60 microg/dL for TT4, 1.12 +/- 0.20 ng/mL for TT3, 29.0 +/- 1.88 for RT3U, 7.54 +/- 1.34 for FT4I, 1.07 +/- 0.16 for FT3I, 18.71 +/- 5.89 ng/dL for rT3, and 1.15 +/- 0.6 microU/mL for TSH. Mean TT3/TT4 ratio was 0.14 +/- 0.03. In group 1, TT3, TT4, and TT3/TT4 ratio did not correlate with age, FEV1, PaO2, or inhaled corticosteroids. Similarly, in group 2, TT3 and TT4 were unrelated to the above-mentioned variables; however, there was a strong positive correlation between TT3/TT4 ratio and PaO2 (r =.61, P =.004). IL-6 was within normal limits in all subjects, and it did not correlate with any thyroid hormone either in group 1 or in group 2. It is concluded that in stable COPD, severity of disease through hypoxemia is important in determining the peripheral metabolism of thyroid hormones. Whether this constitutes an adaptation is not known.     

二甲双胍对促甲状腺素影响的初步研究

目的 观察二甲双胍对血清促甲状腺素(TSH)的影响.方法从2型糖尿病患者中,入选原发性甲状腺功能减退症(甲减)患者48例,组1单用二甲双胍而未予左旋甲状腺素(L-T4)替代治疗(n=17),组2给予L-T4稳定替代量的同时加用二甲双胍(n=19),组3用L-T4稳定替代量和非二甲双胍的其他降糖药(n=12).另外20例甲状腺功能正常的其他甲状腺疾病患者(组4)和30例无甲状腺疾病的患者(组5)作为对照.各组患者均定期检测血清TSH、FT3、FT4、TT3、TT4及血糖等主要指标的变化.结果 治疗12个月与基线时比较,组1为(5.05±1.07)对(2.61±0.91)mU/L(P＜0.01),组2为(2.67±1.03)对(1.35±0.74)mU/L(P＜0.01),两组的FT3及FT4均无明显变化.15例TSH显著降低的患者中有13例(87%)在停用二甲双胍后8～12周内TSH由(1.30±0.71)回升至(2.58±1.02)mU/L(P＜0.01).组3、组4及组5的血清TSH和甲状腺激素的水平均无明显改变.结论 服用二甲双胍可使TSH下降.

Abstract：

Objective To evaluate the effects of metformin on thyrotropin(TSH)levels. Methods From the patients with type 2 diabetes mellitus or metabolic syndrome, 48 patients with primary hypothyroidism were enrolled and grouped. 17 patients were treated only with metformin(group A), 19 patients with metformin and stable L-T4substitution(group B), and the remaining 12 patients with antidiabetic drugs(other than metformin)and L-T4(group C). Meanwhile, 20 euthyroid patients with other thyroid abnormalities(group D)and 30 patients without thyroid diseases(group E)served as control. TSH, FT3, FT4, TT3, TT4, and blood glucose were determined regularly in all these subjects. Results After administration of metformin for 12 months, serum TSH were decreased in group A [(5.05±1.07 vs 2.61±0.91)mU/L, P＜0.01] and group B [(2.67±1.03 vs 1.35±0.74)mU/L, P＜0.01]. No difference was found in FT3and FT4in both groups. TSH levels were raised from(1.30±0.71)to(2.58±1.02)mU/L(P＜0.01)within 8～12 weeks in 13 out of 15 patients after metformin withdrawal. Serum TSH and thyroid hormones in the other 3 groups were not significantly changed. Conclusion Administration of metformin may lead to reduction of serum TSH level.     

SERUM IODOTHYRONINE CONCENTRATIONS DURING INTRODUCTION OF THYROXINE REPLACEMENT THERAPY IN HYPOTHYROIDISM

Serum concentrations of total and free T4 (TT4 and FT4), total and free T3 (TT3 and FT3), rT3, T4 binding globulin (TBG), T3 uptake (T3U) and TSH were measured in 12 patients with severe hypothyroidism before and during the introduction of replacement therapy with oral T4. The dose of T4 was increased by increments of 50 micrograms at intervals of 4 weeks to a total of 200 micrograms daily. There was a linear correlation between the concentrations of FT3 and FT4 (FT3 = 1.35 + 0.23FT4, r = 0.916, P less than 0.001). The correlation between TT3 and TT4 was more complex: the data were best fitted by the expression TT3 = 0.195 square root TT4, (r = 0.936, P less than 0.001). The relatively greater rise in TT3 initially may reflect a greater binding of T3 by TBG when the concentration of T4 is low. TBG concentration fell after 50 and 100 micrograms of T4 but did not change at the higher doses. There was a simple linear relation between TT4 and rT3 (rT3 = -0.022 + 0.0027TT4, r = 0.921, P less than 0.001). The expected inverse relation between TSH concentration and the thyroid hormones was seen, the three closest correlations being between the logarithm of the TSH concentration and FT3, the ratio T4/TBG and FT4 (r = 0.927, -0.917 and -0.900 respectively). These correlations were significantly better (P less than 0.05) than the correlations with untransformed TSH values. Suppression of TSH occurred while FT3 tended to remain within normal limits, but FT4 was often raised.(ABSTRACT TRUNCATED AT 250 WORDS)