Endocrine Abstracts

Thyroid hormone (TH) is essential for the development of tissues, in particular the brain, and for their metabolic function throughout life. The thyroid secretes mostly the prohormone T4 and a small amount of the active hormone T3. Most T3 is generated by outer ring deiodination of T4 in peripheral tissues, and both T4 and T3 are degraded by inner ring deiodination to inactive metabolites. This involves three di...

Thyroid hormone plays an important role in the development of tissues, in particular the brain, and in the regulation of their metabolic activity throughout life. Most of the actions of thyroid hormone are initiated by binding of T3 to its nuclear receptor, resulting in an altered transcription of thyroid hormone-responsive genes. Also the metabolism of thyroid hormone by the deiodinases D1, D2 and D3 takes place intracellularly. D2 and D3 are important for local regulation of...

The prohormone thyroxine (T4) is the major product secreted by the thyroid gland, while most actions of thyroid hormone (TH) are initiated by binding of the active hormone 3,3′,5-triiodothyronine (T3) to nuclear receptors. The biological activity of TH is thus determined by the intracellular T3 concentration in target tissues, which depends on 1) the circulating concentrations of T4 and T3, 2) the activity of deiodinases catalyzing the conversion of T4 to T3 or to recept...

Action and metabolism of thyroid hormone are intracellular events which require the transport of iodothyronines across the plasma membrane through transporters. In recent years, several transporters have been identified which are capable of transporting thyroid hormone. They are members of different transporter families, including organic anion transporting polypeptides (OATPs) family, heterodimeric amino acid transporters (HATs), and monocarboxylate transporters (MCTs). In pa...

Introduction: Although hCG is an important determinant of gestational thyroid function, it is unknown to what extent hCG is a risk factor for thyroid disease and we also lack knowledge on which characteristics influence the thyroidal response to hCG stimulation.Methods: hCG, TSH, FT4 and TPOAbs were measured in 5435 pregnant women (<18 weeks) in a prospective cohort. Subclinical disease entities were defined according to P2.5-P97.5 in TPOAb negative ...

Context: Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality worldwide, affecting 2–8% of all pregnancies. We have previously shown that women with high-normal levels of FT4 during early pregnancy have a 2.1-fold increased risk of preeclampsia – but there was no apparent association with low TSH. However, the thyroid is stimulated by human chorionic gonadotropin (hCG) during early pregnancy and therefore we hypothesized that women with h...

Background: Recent studies suggest enhanced peripheral thyroid hormone metabolism as an explanation for the changes in thyroid hormone levels in patient treated with Sorafenib.Methods: In this single centre, prospective, observational cohort study 60 patients with hepatocellular carcinoma were treated with Sorafenib. Thyroid stimulating hormone (TSH) and free thyroxine (FT4) were measured at baseline (time-0), at 6 weeks (time-1) and at the end of therap...

Background: The interest in the potential effect of thyromimetics in lowering serum cholesterol is growing. Thyroid hormone actions on lipid metabolism are exerted in the liver and mediated by the T3 receptor TRβ1. The creation of molecules transported into hepatocytes by liver-specific transporters can increase the liver selectivity of thyromimetics. Sodium taurocholate co-transporting polypeptide (NTCP), a solute carrier protein primarily expressed on the basolateral me...

Introduction: POU1F1 is a pituitary transcription factor, critical for differentiation of pituitary somatotrophs, thyrotrophs and lactotrophs. POU1F1 expression depends on the presence of PROP1, which attenuates expression of transcriptional repressor HESX1. Previous mutation screening of POU1F1 coding exons in our cohort of patients with combined pituitary hormone deficiency (CPHD) showed POU1F1 mutations in only 1% of the families. We hypo...

Context: High maternal TSH and/or low FT4 during pregnancy is associated with an increased risk of premature delivery. hCG is the main determinant of thyroid function changes during pregnancy but has a versatile pattern with high inter and intra-individual variability. We hypothesised that the correct interpretation of thyroid function tests and its use in the risk assessment of premature delivery during pregnancy depend on hCG levels.Design, ...