Endocrine Abstracts

The central hypothyroidism (CeH) is a hypothyroid condition due to an insufficient stimulation by TSH of an otherwise normal thyroid gland. CeH is about 1000-fold rarer than primary hypothyroidism (PH). Differently to PH, the CeH is most frequently characterized by low/normal TSH levels and thyroid hormone replacement is associated with the suppression of residual TSH secretion even during low thyroxine regimen.Thus, CH management often represents a clin...

Primary ovarian failure (POF) is defined as a premature ovarian defect characterized by absent menarche (primary amenorrhea) or secondary amenorrhea lasting at least 6 months associated with a premature depletion of ovarian follicles before the age of 40 years. POF is a frequent disease affecting female fertility and well-being and generating several co-morbidities. Since the onset of POF is frequently silent and fertility defects occur in the occult phases of the disease seve...

Congenital hypothyroidism (CH) is the most frequent endocrine congenital defect affecting about 1:3000 newborns. In economically/ socially advanced counties, CH is routinely screened by means of TSH (and/or T4) measurement on dry blood spot (dbs) since more than 20 years. Neonatal screening allows early recognition and treatment of affected newborns. Upon data collected in years <2000 by the Italian CH Registry, the newborns with confirmed CH and gland-in-situ constituted ...

In clinical practice, most thyroid disease is due to thyroid gland dysfunction and so can be detected by measurement of TSH alone. This is because the negative feedback of thyroid hormones on the hypothalamus and pituitary gland result in TSH levels that are closely, and inversely, correlated with circulating free thyroid hormone (FT4, FT3) levels. However, several conditions are exceptions to this rule and can be very hard to diagnose also due to a certa...

Thyroid hormone action defects (THADs) are caused by the defective action of thyroid hormones (THs) through their receptors (TRs). TRs variants (TRα1 or TRβ) are associated with several defects, which depend mainly on the tissue-specific expression of the defective-receptor. One of the most striking manifestations is the deregulation of the hypothalamus–pituitary–thyroid axis (HPT); patients with TRα1-mutations show normal thyroid volume, low T4/T3 and...

Introduction: As in humans, thyroid hormone (TH) plays an essential role on zebrafish development by acting through the specific nuclear receptors (TRα or TRβ) and activating/suppressing the expression of several target genes. In zebrafish, TRα is preferentially expressed in the heart and CNS while the TRβ is mainly expressed in the retina and inner ear, but the specific role of these receptors in the different target tissues is presently unknown. In this s...

Thyroid hormone receptors (TRs) modulate various physiological functions in many organs. The conservation of TRα and TRβ isoforms during evolution of vertebrates suggests different roles for these TRs in thyroid hormone-dependent regulation of gene expression. TRα and TRβ are widely distributed and overlapping in several tissues, and their functional divergence is mainly attributed to their variable tissue expression patterns and intrinsic properties of spe...

The pathogenesis of premature ovarian failure (POF) is largely unknown. However, the evidence of a frequent familiarity for the anticipation of menopause among POF women supports the concept of a strong genetic component at the origin of POF. This is further supported by the findings of several candidate genes and by data coming from natural and experimental animal models. On these bases, several groups are involved in the search for markers able to predict the risk of POF. Th...

The thyroid hormone (TH) feedback is the principal mechanism contributing to maintain the circulating levels of thyroid hormones within the physiological limits that are required for an adequate action at the tissue level. Therefore, circulating TSH determination is considered the most accurate parameter to diagnose a disorder of thyroid function. Several defects are known to be associated with the disruption of such mechanism, but their intimate understanding is still limited...

Thyroid cancer (TC) is the most common endocrine malignancy, with an increasing number of diagnosis in the last decades. Of all TC histotypes, the poorly differentiated and anaplastic TCs (PDTC and ATC) have a very poor prognosis because of their invasiveness and metastatic behavior, as well as their insensitivity to radioactive-iodine treatment. In the last years, the stem-cell model has been proposed to further explain TC carcinogenesis. According to this model, only a subse...