Human cold air habituation is independent of thyroxine and thyrotropin.

Thyroxine (T4) is required in species possessing brown adipose tissue (BAT) for the maintenance of cold tolerance and adaptation. In humans, who possess negligible quantities of BAT, the importance of T4 has not been demonstrated. We studied the effects of decreased serum T4 and thyrotropin (TSH) on human cold habituation after repeated cold air exposures. Eight men (T3+) received a single daily dose of triiodothyronine (T3; 30 micrograms/day), and another eight men (T3-) received a placebo. All 16 normal thyroid men underwent a standardized cold air test (SCAT) under basal conditions in January and again in March after eighty 30-min 4.4 degrees C air exposures (10/wk). Measurements of basal metabolic rate (BMR), O2 consumption (VO2), mean arterial pressure (MAP), plasma norepinephrine (NE), serum TSH, free and total T4, and free and total T3 were repeated before and after 8 wk of exposure. TSH, free T4, and total T4 were 50% lower for T3+ than for T3- subjects. Total and free T3 were not different between groups. BMR was unchanged after habituation, whereas the cold-stimulated VO2, MAP, and NE were significantly reduced for all subjects in March. The relationship between VO2 and NE (r2 = 0.44, P less than 0.001) during the initial SCAT was unchanged with habituation. We suggest that human cold habituation is independent of major changes in circulating T4 and TSH.     

Analysis of overall pathophysiological relationships between serum levels of TSH and thyroid hormones using a large laboratory database

Factors associated with the basal level of serum thyrotropin (TSH) were analyzed over a wide range of pathophysiological conditions by means of a large laboratory database on thyroid function. When data were analyzed two-dimensionally, serum TSH showed significant inverse correlations with total triiodothyronine (T3), free T3 index (FT3I), total thyroxin (TT4) and free T4 index (FT4I) in the order of increasing intensity. The three-dimensional analysis, however, revealed that 1) total hormone levels were actually unrelated to serum TSH when the levels of free hormone indices were held constant, 2) the relation between FT3I and TSH became obscure when the influence of FT4I was similarly removed. On the other hand, 3) the relation of FT4I with TSH was unaffected by the level of FT3I. These results suggest that free T4 is the main determinant of the serum TSH level. This study also implies that it is possible to use large amounts of laboratory data to elucidate the overall profile of a given patho-physiological system, whose structure is only partially revealed by conventional clinical or animal studies.     

Serum thyrotropin response to thyrotropin-releasing hormone and free thyroid hormone indices in patients with familial thyroxine-binding globulin deficiency.

The response in serum thyrotropin (TSH) to synthetic thyrotropin-releasing hormone (TRH) as well as serum free thyroxine index (FT4I) and free triiodothyronine index (FT3I) was investigated in six patients with familial thyroxine-binding-globulin (TBG) deficiency. The total serum thyroxine (T4) and triiodothyronine (T3) concentrations were significantly decreased, compared with those of normal subjects (3.4 +/- 0.9 microgram/dl, mean +/- SD. vs. 9.0 +/- 1.5 microgram/dl, p less than 0.01 and 87 +/- 27 ng/dl vs. 153 +/- 37 ng/dl, p less than 0.01, respectively). FT4I was lower than the normal range in all but one (5.3 +/- 1.5 vs. 8.9 +/- 1.6, p less than 0.01), whereas FT3I was all in the normal range and of no significant difference from the normal control (132 +/- 22 vs. 148 +/- 25). Serum TSH concentrations in TBG deficiency were all in the normal range (1.0-4.2 muU/ml) and the maximum TSH increments following TRH 500 microgram iv were 8.9 +/- 2.0 muU/ml and of no significant difference from the normal control (10.2 +/- 4.5 muU/ml). These results indicate that the euthyroid state in familial TBG deficiency is more clearly defined by TRH-test and the normal response to TRH in familial TBG deficiency is presumably under the control of the serum free T3 level rather than the serum free T4 level.     

Abnormalities in pituitary thyroid axis function tests in patients with paroxysmal supraventricular arrhythmias

The study was carried out on 60 consecutive patients (23 males and 37 females) aged between 20 and 83 years (means +/- SD, 40.7 +/- 16) who arrived at our Cardiologic Unit with paroxysmal supraventricular arrhythmias (PSVA) including junctional paroxysmal tachycardia (n = 32), atrial fibrillation (n = 13), atrial flutter (n = 1), premature beats (n = 13) and with no obvious cardiovascular causes. Serum thyroxine and triiodothyronine were normal in all patients and thyroid scintiscan revealed normal shape and size thyroids without autonomously functioning nodule(s). Thyrotropin (TSH) response to thyrotropin releasing hormone (TRH) was normal in 44 subjects in whom normal serum free T4 (FT4) and free T3 (FT3) levels were measured. Six patients with normal FT4 and FT3 levels did not respond to TRH. Abnormalities in thyrotropin response to TRH were observed in 10 patients all exhibiting increased FT4 or also FT3 levels. Among these, 5 patients did not respond to TRH, whereas the remaining 5 exhibited a blunted TSH response to TRH. These results suggest that only in a small proportion (5/60) of consecutive patients with PSVA it is possible to recognize a status of "occult thyrotoxicosis" on the basis of the combined evaluation of free thyroid hormones and TSH response to TRH.     

The pituitary-thyroid axis in acromegaly

The pituitary-thyroid axis of 12 acromegalic patients was evaluated by measurement of the serum concentrations (total and free) of thyroxine (T4), triiodothyronine (T3) and reverse T3 (rT3) and thyrotropin (TSH), growth hormone (GH) and prolactin (PRL) before and after iv stimulation with thyrotropin releasing hormone (TRH). Using an ultrasensitive method of TSH measurement (IRMA) basal serum TSH levels of the patients (0.76, 0.07-1.90 mIU/l) were found slightly, but significantly (P less than 0.01), lower than in 40 healthy controls (1.40, 0.41-2.50 mIU/l). The total T4 levels (TT4) were also reduced (84, 69-106 nmol/l vs 100, 72-156 nmol/l, P less than 0.01) and significantly correlated (P less than 0.02, R = 0.69) to the TSH response to TRH, suggesting a slight central hypothyroidism. The acromegalics had, however, normal serum levels of TT3 (1.79, 1.23-2.52 nmol/l vs 1.74, 0.78-2.84 nmol/l, P greater than 0.10), but significantly decreased levels of TrT3 (0.173, 0.077-0.430 nmol/l vs 0.368, 0.154-0.584 nmol/l, P less than 0.01) compared to the controls. The serum concentration of the free iodothyronines (FT4, FT3, FrT3) showed similar differences between acromegalics and normal controls. All the acromegalics showed a rise of serum TSH, GH and PRL after TRH. Positive correlation (P less than 0.05, R = 0.59) was found between the TSH and GH responses, but not between these two parameters and the PRL response to TRH. These findings may be explained by the existence of a central suppression of the TSH and GH secretion in acromegalic subjects, possibly exerted by somatostatin. Euthyroidism might be maintained by an increased extrathyroidal conversion of T4 to T3.     

Thyrotropin-secreting pituitary adenoma: a case report.

We report a 44-year-old male with a thyrotropin (TSH)-secreting pituitary adenoma. Based serum free triiodothyronine (FT3, 12.1 pmol/l) and free thyroxine (FT4, 28 pmol/l) were increased with normal basal TSH (3.1 mU/l). There was impaired TSH response to thyrotropin releasing hormone (TRH) test. Serum TSH was suppressed to 59% of the basal level after oral administration of 1.4 mg 3,3'-5-triiodothyroacetic acid (triac), whereas no suppression was observed after 75 micrograms daily administration of triiodothyronine (T3). Serum concentrations of alpha-subunit of TSH (TSH-alpha) and TSH-alpha/TSH molar ratio were high, being 1.95 micrograms/l, and 4.4, respectively. Pituitary CT and MRI scan showed the presence of a macroadenoma in the anterior lobe of the pituitary gland. Histopathology of the excised pituitary confirmed the diagnosis of a TSH-producing adenoma. A positive correlation between TSH and FT3 (r = 0.66, P less than 0.01) or FT4 (r = 0.54, P less than 0.01) was observed in serial sera obtained before and after operation.     

Thyroid Function and Serum Copper,Selenium, and Zinc in General U.S. Population

Association of the levels of serum selenium (Se), zinc (Zn), and copper (Cu) with thyroid function was assessed by analyzing data from National Health and Nutrition Examination Survey for the cycle 2011–2012. Thyroid function variables analyzed were as follows: thyroid-stimulating hormone (TSH), free and total triiodothyronine (FT3, TT3), free and total thyroxine (FT4, TT4), and thyroglobulin (TGN). Regression models with log-transformed values of thyroid hormones as independent variables and age, race/ethnicity, smoking and iodine sufficiency status, respondents’ education, and levels of Se, Zn, and Cu as dependent variables were fitted. For males, levels of Zn were associated with decreased levels of FT4 and TT4, and levels of Cu were associated with increased levels of FT4 and TT4. For females, levels of Cu were associated with increased levels of TT3 and TT4. Smoking was found to be associated with lower levels of TSH and higher levels of TGN in males. Smoking was found to be associated with lower levels of TT4 in females. Males had about 5–10 % higher levels of both Se and Zn, but as much as 20 % lower levels of Cu than females. Smoking was associated with lower levels of Zn, but higher levels of Cu in males.     

The pituitary-thyroid axis in patients with pituitary disorders

The pituitary-thyroid axis of 12 patients, exposed to transsphenoidal pituitary microsurgery because of nonfunctioning adenomas (6), prolactinomas (3) and craniopharyngioma (1), or to major pituitary injury (1 apoplexy, 1 accidental injury), was controlled more than 6 months following the incidents. The patients did not receive thyroid replacement therapy and were evaluated by measurement of the serum concentration of thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), T3-resin uptake test and thyrotropin (TSH, IRMA method) before and after 200 micrograms thyrotropin releasing hormone (TRH) iv. The examination also included measurement of prolactin (PRL) and cortisol (C) in serum. Apart from 1 patient with pituitary apoplexy all had normal basal TSH levels and 9 showed a significant TSH response to TRH. Compared to 40 normal control subjects the 12 patients had significantly decreased levels of T4, T3 and rT3 (expressed in free indices), while the TSH levels showed no change. Five of the patients, studied before and following surgery, had all decreased and subnormal FT4I (free T4 index) after surgery, but unchanged FT3I and TSH. The levels of FT4I were positively correlated to both those of FT3I and FrT3I, but not to TSH. The TSH and thyroid hormone values showed no relationship to the levels of PRL or C of the patients exposed to surgery. It is concluded that the risk of hypothyroidism in patients exposed to pituitary microsurgery is not appearing from the TSH response to TRH, but from the thyroid hormone levels.     

Changes in the hypothalamic-pituitary-thyroid axis during acute starvation in non-obese patients

We investigated changes in the hypothalamic-pituitary-thyroid axis before, during, and after fasting in twenty-one non-obese euthyroid patients with psychosomatic diseases. Blood samples for free T3 (FT3), T3, free T4 (FT4), T4, reverse T3 (rT3), and TSH were obtained from all patients before and on the 5th day of fasting, and in 11 of the same individuals on the 5th day of refeeding. Serum TSH and T3 responses to TRH were also evaluated in 10 patients before and on the 5th day of fasting. During the fast, FT3, T3 and TSH levels decreased significantly and rT3 levels increased significantly whereas FT4 and T4 levels remained within the normal range. Maximal delta TSH, peak TSH levels, max delta T3, peak T3 levels, and net secretory responses to TRH decreased significantly. Peak TSH levels and max delta TSH to TRH correlated well with basal levels of TSH. A statistically significant negative correlation between basal levels of FT4 and TSH was observed. After refeeding, there was a significant increase only in TSH which returned to prefasting values. These results demonstrated that in a state of "low T3" during acute starvation a reduction in serum T3 might depend partly on TSH-mediated thyroidal secretion.     

Anomalies in thyroid function in children with trisomy 21

Thyroid function of 60 children with Down (DS) aged 3 months to 16 years was studied by evaluation of serum concentration of ultra-sensitive thyroid stimulating hormone (TSH), free T4 and T3 (FT4, FT3), total T4 and T3 (T4 and T3) and reverse T3 (rT3). Each DS child was matched to a control of the same age. The concentration of TSH was increased in DS children while the concentration of rT3 of the DS children was significantly decreased compared to the controls as was the ratio rT3/TSH. These results showed that thyroid function of DS children is abnormal.     

131I对男性甲状腺功能亢进症血清性激素及甲状腺球蛋白水平影响研究

目的:探讨~(131)I对男性甲状腺功能亢进症患者血清性激素及甲状腺球蛋白水平的影响。方法:收集我院收治的男性甲状腺功能亢进症患者74例,随机分为对照组和实验组,每组各37例,对照组患者给予他巴唑口服,20-30 mg/次,每日口服1次。实验组患者在对照组基础上给予~(131)I治疗。治疗结束后,检测并比较两组患者血清游离三碘甲状腺素(FT3)、游离甲状腺素(FT4)、促甲状腺激素(TSH)、睾酮(T)、雌二醇(E2)、甲状腺球蛋白(TG)水平的变化以及临床疗效。结果:与治疗前相比,两组患者血清FT3、FT4、T、E2、TG水平均显著下降,TSH水平明显升高(P0.05);与对照组相比,实验组患者血清FT3、FT4、T、E2、TG水平较低,TSH水平以及临床治疗有效率较高(P0.05)。结论:~(131)I能够显著降低男性甲状腺功能亢进症血清FT3、FT4、T、E2、TG水平,升高TSH水平,临床效果较好。     

The Effect and Potential Mechanism Analysis of Growth Hormone–Secreting Pituitary Adenomas on Thyroid Function

ObjectiveCurrent studies on the effect of high growth hormone (GH)/insulin-like growth factor (IGF)-1 on thyroid function are inconsistent. The aim was to explore the effect and potential mechanism of high GH/IGF-1 on thyroid function by analyzing the changes of thyroid function in patients with growth hormone–secreting pituitary adenoma (GHPA).MethodsThis was a retrospective cross-sectional study. Demographic and clinical data of 351 patients with GHPA who were first admitted to Beijing Tiantan Hospital, Capital Medical University, from 2015 to 2022 were collected to analyze the relationship between high GH/IGF-1 levels and thyroid function.ResultsGH was negatively correlated with total thyroxine (TT4), free thyroxine (FT4), and thyroid-stimulating hormone (TSH). IGF-1 was positively correlated with total triiodothyronine (TT3), free triiodothyronine (FT3), and FT4 and negatively correlated with TSH. Insulin-like growth factor–binding protein (IGFBP)-3 was positively correlated with TT3, FT3, and FT3:FT4 ratio. The FT3, TT3, TSH, and FT3:FT4 ratio of patients with GHPA and diabetes mellitus (DM) were significantly lower than those with GHPA but without DM. With the increase of tumor volume, thyroid function gradually decreased. GH and IGF-1 were correlated negatively with age in patients with GHPA.ConclusionThe study emphasized the complex interaction between the GH and the thyroid axes in patients with GHPA and highlighted the potential effect of glycemic status and tumor volume on thyroid function.     

Thyroid functions in patients with various chronic liver diseases

In order to clarify an alteration in thyroid functions in patients with chronic liver diseases, serum total and free thyroxine (T4, FT4), total and free triiodothyronine (T3, FT3), total reverse T3 (rT3), thyrotropin (TSH), thyroxine-binding globulin (TBG) concentrations, and T3 uptake (T3U) were measured by radioimmunoassays in 53 patients with chronic hepatitis (CH), 24 patients with compensated liver cirrhosis (LC), 17 patients with hepatocellular carcinoma associated with LC (HCC), and 40 normal subjects. Serum T4, T3, and rT3 in CH, and serum rT3 in HCC were significantly increased, while serum T4 in LC and serum T3 in HCC were significantly decreased. Serum TBG was increased and T3U was decreased in these patients. Serum TBG in CH and LC correlated positively with transaminase, and inversely with prothrombin time. FT4 and T4/TBG ratios in CH and LC and FT3 and T3/TBG ratios in LC and HCC were significantly decreased. Although T4/TBG ratios in HCC and T3/TBG ratios in CH were significantly decreased, FT4 in HCC and FT3 in CH were not decreased. The ratio of rT3/T3 in CH and LC correlated with various liver function tests. FT3 in LC and HCC correlated inversely with BSP (45') and positively with KICG. No differences in serum TSH values were found between chronic liver diseases and normal subjects. From these results, it was concluded that the thyroid functions in patients with chronic liver diseases were affected by the decrease in serum thyroxine, elevated serum TBG, the degree of which is in proportion to that of the liver cell damage, and impaired peripheral conversion of T4 to T3, the degree of which is in proportion to that of the hepatic dysfunction.     

A case of hypothyroidism with simultaneous presence of stimulating type anti-thyrotropin (TSH) receptor antibodies and anti-thyroxine (T4) autoantibodies.

We have examined a hypothyroid patient with stimulating type anti-thyrotropin (TSH) receptor antibodies and without blocking type anti-TSH receptor antibodies. Although she had high serum TSH (240 microU/ml) and low free triiodothyronine (FT3, 0.49 pg/ml) concentrations, which agree with physical findings of hypothyroidism, she had an unusually high free thyroxine (FT4) concentration (3.56 ng/dl). Incubation of her serum with 125I-T4, followed by precipitation with 12.5% polyethylene glycol (PEG) disclosed a higher binding of 125I-T4 (34.4%) than in normal controls, being 5-7%. In addition, binding of 125I-T4 to her serum gamma-globulin was completely displaced by the addition of unlabelled T4. From these results it was concluded that her serum contained anti-T4 autoantibodies. Treatment with synthetic T4 was begun and her thyroid function was monitored by sensitive TSH radioimmunoassay (RIA) and RIA of FT4 after PEG treatment. Since both sensitive TSH RIA and FT4 RIA results after PEG treatment give results concordant with the physical findings, it was concluded that both of the RIA results are useful for the evaluation of thyroid function in patients with thyroid hormone autoantibodies.     

Thyroid function tests in children with congenital hypothyroidism on L-thyroxine treatment

The plasma levels of thyroxine (T4), triiodothyronine (T3), free T4 (FT4), free T3 (FT3), reverse T3 (rT3) and immunoradiometrically assayed thyrotropin (IRMA TSH) have been measured in 28 L-T4-treated children with congenital hypothyroidism as well as in a control group (group C). The patients were subdivided into 2 groups according to the nonsuppressed (group A) or suppressed (group B) TSH response to TSH-releasing hormone (TRH). Basal IRMA TSH correlated with the TSH increment after TRH and it was significantly lower in group B vs. groups A and C, while no difference was present between groups A and B in regard to T4, FT4 and rT3, all higher than in group C. FT3 levels were similar in the 3 groups. In children, as in adults, basal IRMA TSH seems to be a reliable index in monitoring overtreatment.     

Serum thyroid hormone profile and trace elements in children receiving valproic acid therapy: A longitudinal and controlled study

Valproic acid (VPA) may affect thyroid hormone profile, causing alteration in serum trace elements concentrations. The aim of this study was to prospectively investigate this relationship in children receiving VPA monotherapy for a period up to 6 months. Serum thyrotropin (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroxine (T4), triiodothyronine (T3), thyroglobuline (TG), selenium (Se), zinc (Zn), and copper (Cu) levels were evaluated at baseline and at the 6th month in all the patients and in the control group. The mean Cu concentration in the 6th months of VPA therapy was significantly lower than that of the control group. TSH level was significantly increased in the patient group whereas FT4 was significantly decreased. The mean TSH level in the 6th month of VPA therapy was significantly higher than that of the control group, whereas mean T4 level was significantly lower. The Cu level in the 6th months of VPA therapy was positively correlated with T4 level. Δlog Cu and ΔTSH were negatively correlated. This study suggests that the alteration in the serum thyroid hormone profile during VPA therapy may result from the reduction in serum Cu levels.     

养殖中华鲟的产后康复

通过观测初次繁殖养殖中华鲟(Acipenser sinensis)亲本产后的摄食行为, 测量生长指标和监测血清中甲状腺指标、血液理化指标, 进行产后亲本11个月康复的效果分析。结果表明: 使用多春鱼(Mallotus villosus)可诱导产后亲本开口摄食及转食营养丰富的混合鲜饵。雌性产后身体虚弱, 摄食时行为异常, 随摄入营养水平逐渐提高, 雌性和雄性最大摄食量于产后7个月时分别达到体质量的2.04%和1.60%, 7个月后恢复正常。随混合鲜饵摄食量提高, 亲本体质量从下降转而升高(9个月间雌雄亲本增长率分别为44.16%和23.30%), 体长增长(增长率分别为5.00%和3.23%), 与同龄未产的养殖中华鲟(参照组)相比, 体质量和体长的增长率均处于较高水平。产后亲本血清总T3(TT3)、血清总T4(TT4)、血清游离T3(FT3)、血清游离T4(FT4)和多项血液理化指标在恢复培养期明显升高, 至培养期末, TT3 、FT3高于参照组, 其余指标多接近参照组平均水平, 表明产后亲本生理情况基本恢复。研究表明, 加强产后康复培养, 可以提高初次繁殖亲本, 尤其是雌性的健康恢复和生长效果, 对养殖中华鲟资源的重复利用和再次成熟后生殖力的提高至关重要。       

Apparent increase in type I 5'-deiodinase activity induced by antiepileptic medication in mentally retarded subjects

BACKGROUND/OBJECTIVES: Thyroid function measurements in 3 mentally retarded patients treated with antiepileptic drugs (phenytoin or carbamazepine) showed normal thyroid-stimulating hormone (TSH) responses in spite of markedly low levels of total thyroxine (T(4)), triiodothyronine (T(3)), and free thyroxine (FT(4)) concentrations; free triiodothyronine (FT(3)), as well as mean thyroxine-binding globulin (TBG) concentrations were normal. The objective of the present investigations was to determine if antiepileptic medication in these patients contributed to the disparate TSH and thyroid hormone (TH) levels. METHODS: Thyroid tests and other laboratory parameters were measured by conventional techniques. RESULTS: Circulating TH changes noted in retarded patients were similar to those observed in control subjects receiving carbamazepine alone. Reverse T(3) (rT(3)) levels in all patients were either undetectable or below the normal range. CONCLUSIONS: As type I 5'-deiodinase has a higher affinity for rT(3) than T(4), an increased activity of this enzyme would enhance rT(3) deiodination and reduce serum rT(3) concentration whereas enhanced T(4) deiodination would aid in normalizing intracellular FT(3) concentration. The finding of normal serum FT(3) concentration was consistent with normal TSH response and clinical euthyroidism in both retarded and control subjects. While phenytoin-induced increase in type I 5'-deiodinase has been previously noted, the present studies demonstrate a similar effect of carbamazepine on 5'-deiodinase.     

模拟海拔5 500 m低压低氧环境对大鼠HPT轴和肠道菌群的影响*

目的: 探究模拟海拔5 500 m低压低氧环境对大鼠下丘脑-垂体-甲状腺(HPT)轴和肠道菌群的影响及两者间关联。方法: 采用低压低氧舱模拟海拔5 500 m高度,构建成年雄性SD大鼠低氧模型,设置1、3、7、14、21和28 d低氧组和常氧组,并设置1 d和3 d低氧后常氧恢复组(每组大鼠8只,低氧时间为每天24 h)。记录大鼠每日体重和平均摄食量,采用16 s rDNA测序分析肠道菌群、ELISA检测血清HPT轴激素水平,进行肠道菌群与HPT轴激素相关性分析。结果: 与常氧组相比,低氧组大鼠体重和摄食量显著降低(P＜0.01)。1 d、3 d低氧组大鼠血清促甲状腺素释放激素(TRH)和促甲状腺激素(TSH)水平较常氧组显著降低(P＜0.05),血清总甲状腺素(TT4)、总三碘甲状腺原氨酸(TT3)、游离甲状腺素(FT4)和游离三碘甲状腺原氨酸(FT3)水平较常氧组显著增加(P＜0.05)。1和3 d低氧组大鼠肠道副拟杆菌属(Parabacteroides)、乳酸杆菌属(Lactobacillus)、丁酸球菌属(Butyricimonas)、拟杆菌属(Bacteroides)、臭味杆菌属(Odoribacter)和RC4-4菌属丰度较常氧组显著增加(P＜0.05),普氏菌属(Prevotella)丰度较常氧组显著降低(P＜0.05)。14、21和28 d低氧组大鼠副拟杆菌属、球毛菌属(Sphaerochaeta)、阿克曼氏菌属(Akkermansia)、迷踪菌属(Elusimicrobium)丰度较常氧组显著增加(P＜0.05),乳酸杆菌属、萨特氏菌属(Sutterella)丰度较常氧组显著降低(P＜0.05)。肠道菌群与HPT轴激素相关性分析表明,丁酸球菌属、迷踪菌属、萨特氏菌属与TRH、TSH显著负相关(P＜0.05),普氏菌属、拟杆菌属、臭味杆菌属、副拟杆菌属分别与TSH、TT4、TT3、FT4显著相关(P＜0.05),乳酸杆菌属与TRH、 TSH、FT4显著相关(P＜0.05),阿克曼氏菌属与TRH、FT4显著相关(P＜ 0.05),RC4-4菌属与TSH、TT3显著相关(P＜0.05)。结论: 模拟海拔5 500 m低氧应激显著改变SD大鼠肠道菌群的构成,这可能是甲状腺功能与低氧环境相适应的变化,变化程度与低氧应激时间有关;低氧环境下大鼠肠道菌群的变化与HPT轴激素水平显著相关。     

Goiter and impairment of thyroid function in acromegalic patients: basal evaluation and follow-up.

AIMS: We evaluated morphological, biochemical and cytological thyroid parameters in acromegalic patients, investigated before and after treatment for acromegaly. PATIENTS: 28 acromegalics were investigated before and, in 18 cases, after 2-7 years of therapy. Fourteen patients were from areas of moderate iodine deficiency in Southern Italy. One patient underwent thyroidectomy before entering this study. RESULTS: 19 patients were euthyroid (FT4: 17.7 +/- 0.8 pmol/l and FT3 4.6 +/- 0.2 pmol/l), but TSH was undetectable in 5/19. Among them, TRH-stimulated TSH increase was absent/impaired or exaggerated/delayed in 9 and one cases, respectively. Decreased FT3 and/or FT4 values with low/normal TSH values were detected in 7 cases; TRH-stimulated TSH response was absent/impaired in 2 patients and exaggerated/delayed in another two. Increased free T4 and free T3 concentrations with undetectable TSH levels were found in one. Two euthyroid patients had high TPOAb levels. Goiter was diagnosed in 21 cases and nodules were found in 14/21. 99Tc scintiscan showed "cold" areas in 13/14 cases and a "hot" nodule in the hyperthyroid patient. Acromegalics from iodine deficient areas showed a not significant increase of prevalence of goiter (86 vs. 71 %) and of mean thyroid volume (35 +/- 7 vs. 28 +/- 4 ml, NS), compared to others. Thyroid volume (TV) did not correlate with GH, IGF-1 and TSH levels, the area under the curve of insulin-increase during OGTT, the age of patients or the duration of acromegaly. Fine needle aspiration biopsy (FNAB), performed in 11/14 patients with nodular goiter, showed colloid nodules in 8 cases, hyperplastic nodules in 2 and an adenomatous nodule in one. Neurosurgery, radiotherapy or medical treatment for acromegaly induced a significant decrease of mean GH and IGF-1 levels (21.5 +/- 8.5 vs. 12.9 +/- 9.6 ng/ml, p< 0.005 and 747 +/- 94 vs. 503 +/- 88 ng/ml, p < 0.02, respectively), but both GH and IGF-1 values normalized only in 3 cases. No significant variation of mean TSH levels was found. Although TV normalized in 3 patients, ultrasound evaluation showed a not significant decrease of mean TV and no changes in the diameter and number of nodules. FNAB was unchanged. CONCLUSIONS: Our results suggest that, despite no correlation between serum GH and IGF-1 levels and thyroid volume being found, a decrease in serum GH and IGF-1 levels has favourable effects on thyroid status.