High free triiodothyronine and free-triiodothyronine-to-free-thyroxine ratio levels are associated with metabolic syndrome in a euthyroid population

Aims

To determine the association between free triiodothyronine (FT3), free thyroxine (FT4) and free-triiodothyronine-to-free-thyroxine ratio (FT3/FT4) levels and Metabolic Syndrome (MetS).

T3对体外培养的大鼠胚胎大脑神经细胞神经递质代谢的影响

本文采用无血清培养液(SFM),加入生理浓度的 T_3,观察 T_3对15—18天大鼠胚胎大脑神经细胞神经递质代谢的影响。发现 T_3能明显促进体外培养的胎鼠大脑神经细胞合成,分泌单胺类神经递质,促进神经细胞发育成熟。     

Thyroid function testing in elephant seals in health and disease

Northern Elephant Seal Skin Disease (NESSD) is a severe, ulcerative, skin condition of unknown cause affecting primarily yearling northern elephant seals (Mirounga angustirostris); it has been associated with decreased levels of circulating thyroxine (T4) and triiodothyronine (T3). Abnormalities of the thyroid gland that result in decreased hormone levels (hypothyroidism) can result in hair loss, scaling and secondary skin infections. However, concurrent illness (including skin ailments) can suppress basal levels of thyroid hormones and mimic hypothyroidism; when this occurs in animals with normal thyroid glands it is called "sick euthyroid syndrome". The two conditions (true hypothyroidism vs. "sick euthyroid") can be distinguished in dogs by testing the response of the thyroid gland to exogenous thyrotropin (Thyroid Stimulating Hormone, TSH). To determine whether hypothyroidism is involved in the etiology of NESSD, we tested thyroid function of stranded yearling elephant seals in the following categories: healthy seals (rehabilitated and ready for release; N=9), seals suffering from NESSD (N=16) and seals with other illnesses (e.g., lungworm pneumonia; N=10). Levels of T4 increased significantly for all three categories of elephant seals following TSH stimulation, suggesting that seals with NESSD are "sick euthyroid" and that the disease is not associated with abnormal thyroid gland function.     

冠状动脉旁路移植手术方式对甲状腺激素代谢的影响

目的观察体外循环（on-pump）心脏停跳下和非体外循环（off-pump）心脏不停跳冠状动脉旁路移植手术围术期甲状腺激素的变化规律。方法冠脉旁路手术病人40例，分为Off-pump组和Onpump组，每组20例，分别测定围术期甲状腺功能指标。结果术前两组病例甲状腺功能指标均在正常值范围内。Off-pump组T3和FT3术后显著下降，术后第1d降至最低[（T3：（39．7±6．2）ng，dl对（78．6±12．1）mg/dl，P〈0．01；FT3（1．6±0．5）pg/ml对（2．4±0．6）pg/ml，P〈0．05]；T4在正常值范围内变化，术后第1d降至最低[（5．3±0．8）μg/dl对（7．2±0．7）μg/dl，P〈0．05]；FT4在正常值范围内波动，各阶段检测值与术前差异无统计学意义（P〉0．05）；rT3术后逐渐升高，术后第3d达高峰[（82．1±26．8）ng/dl对（42．3±15．6）ng/dl，P〈0．01]；TSH术中逐渐下降，术后第1d降至最低[（0．4±0．2）tdU／ml对（1．3±0．6）μIU／ml，P〈0．01]，术后第7d恢复术前水平。围术期两组病例甲状腺功能指标变化趋势相似，差异无统计学意义（P〉0．05）。结论On-pump与Off-pump下冠状动脉旁路移植手术均影响甲状腺激素代谢，两组病人术后均存在低B综合征。     

妊娠早期甲状腺激素水平与妊娠期糖尿病的相关性研究

目的探讨甲状腺激素水平与妊娠期糖尿病(gestational diabetes mellitus, GDM)的相关性。 方法选择2013年1月至2014年12月在广州医科大学附属第六医院门诊进行规律产前检查的1 329例孕妇为研究对象进行回顾性研究,所有孕妇均在11～13^＋6周行甲状腺功能检测并于24～28周行口服葡萄糖耐量试验,315例GDM患者为研究组,1 014例糖耐量正常患者为对照组,分析两组患者的年龄、甲状腺激素水平与GDM的相关性。 结果(1)年龄：研究组年龄为(28.7±5.2)岁,对照组为(27.5±4.5)岁,研究组较对照组高(t＝3.815,P<0.001);(2)游离型四碘甲状腺原氨酸(FT₄)：研究组为(9.59±2.18)pmol/L,较对照组(10.04±2.97)pmol/L降低,两组比较(t＝－2.479,P<0.05);(3)Logistic回归分析提示：FT₄为GDM保护因素(OR＝0.912,95%CI为0.851～0.977),年龄为危险因素(OR＝ 1.049,95%CI为1.022～1.078)。 结论妊娠早期FT₄水平和高龄与妊娠期糖尿病发生相关。     

舒张性心衰患者血清三碘甲状腺原氨酸与脑利钠肽的关系

目的:探讨舒张性心衰(DHF)患者血清三碘甲状腺原氨酸(T3)与脑利钠肽(BNP)的关系。方法:96例慢性舒张性心力衰竭患者测定血清T3和BNP浓度。其中低T3血症的舒张性心衰患者45例(低T3组),血清T3水平正常的舒张性心衰患者51例(正常T3组),观察两组BNP水平。结果:低T3组与正常T3组的舒张性心衰患者血清BNP水平均高于正常,两组分别为(557.4±92.4)ng/L和(308.9±84.6)ng/L,低T3血症组的BNP水平显著升高(P0.01)。结论:舒张性心衰伴低T3血症患者,血清BNP升高更明显。     

The effect of neuroendocrine secretion on brain morphology and EEG sleep in patients with eating disorders

Summary Neuroendocrine disturbances [low plasma levels of triiodothyronine (T3), high plasma concentrations of cortisol], morphological brain alterations [enlarged external cerebrospinal fluid (CSF) spaces, dilatation of the ventricles] and altered sleep patterns [fragmented sleep continuity, a reduction of slow wave sleep (SWS) or REM sleep] have been described in patients with anorexia nervosa and bulimia nervosa. The present study investigates to what degree these disturbances interact with each other. In ten anorexic and five bulimic patients cranial computed tomography (CT) to estimate the size of the CSF spaces, blood sampling to measure cortisol and T3 plasma concentrations, and all-night polysomnography were performed. In comparison with patients with normal CT scans, the patients displaying enlarged CSF spaces spent more time in SWS, and the duration of REM sleep was reduced. In the whole sample, a negative correlation was found between the amount of REM sleep and cortisol, whereas a positive association was found between the amount of REM sleep and the T3 level. In addition, the degree of brain shrinkage correlated positively with cortisol and negatively with T3. On the basis of these results, it can be assumed that in patients with eating disorders the disease process with its neuroendocrine alterations affects brain morphology as well as EEG sleep.     

Saturable uptake of [I] -triiodothyronine at the basolateral (blood) and apical (cerebrospinal fluid) sides of the isolated perfused sheep choroid plexus

The uptake of ¹²⁵I-labelled -triiodothyronine (T₃) was measured on the blood side of the isolated perfused choroid plexus of the sheep using steady-state and single-circulation paired tracer techniques. The steady-stake uptake of T₃ was 33.5% (perfussion fluid protein content was 0.05 g·dl⁻¹) which could be reduced to 9.4% in the presence of 500 μM unlabelled T₃ showing partial saturation. The CSF to blood steady-state [¹²⁵I]T₃ measurements gave plasma/CSF ratio, R%, of 24.6 ± 4.8% which was reduced to 9.8 ± 2.1% in the presence of 500 μM unlabelled T₃ in the mock CSF. The transport of T₃ across the blood face of the choroid plexus and the CSF to blood transport, failed to show sodium dependence. Using the single circulation paired tracer technique, the initial uptake in less than 60 s, U_max of [¹²⁵I]T₃ was 50.4 ± 3.9% relative to the extracellular marker [³H] -mannitol. However, when 250 μM unlabelled T₃ was present, U_max was reduced by 66%, although further significant inhibition at higher concentrations was not observed. Uptake of T₃ at the blood side of the choroid plexus was partially saturated in the presence of unlabelled reverse T₃ and DT₃, suggesting little uptake stereospecificity. Unlabelled thyroxine (T₄) and the amino acid analogues cycloleucine (aminocyclopentane-1-carboxylic acid) and BCH (β-2-aminobicyclo-[2,2,1]-heptane-2-carboxylic acid) each reduced [¹²⁵I]T₃ uptake significantly, but not to the same degree as T₃ stereoisomers. The neutral amino acids alanine and phenylalanine, had no effect on uptake. The [¹²⁵I]T₃ unidirectional flux was calculated from U_max vlues and the resultant kinetic curve could be resolved into two components; a non-saturable process with a slope of 1.2 ml·min⁻¹·g⁻¹, and a saturable process with K_m = 66 ± 22 μM and V_max = 0.44 ± 0.11 μmol·min⁻¹·g⁻¹. These data suggest that [¹²⁵I]T₃ uptake at the blood face of the choroid plexus, is mediated by both saturable and non-saturable uptake processes, which lack stereospecificity, sodium dependence, and exhibit cross competition both with T₄ and the large neutral amino acid analogues, cycloleucine and BCH. Transport from CSF was also partially saturable, did not exhibit sodium dependence.     

Inability of human adipose tissue cells to differenciate between triiodothyronine (T3) and Thyroxine (T4)

Summary The uptake of radioactive T₃ and T₄ by human adipose tissue and isolated adipocytes was investigated. It has been found that the absence of different uptake of T₃ and T₄ in human adipose tissue (in comparison to e.g. muscle) is not caused by interstitial connective tissue, but is the inherent feature of adipose tissue cells.