Endocrine Abstracts

Background: The initiation of puberty is heralded by increasing gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus. During embryonic life the GnRH neuroendocrine network develops thanks to a coordinated migration of neurons from the nasal placode to the forebrain. Our group has previously demonstrated that dysregulation in GnRH neuronal migration leads to delayed pubertal onset. Late puberty affects up to 2% of the population and is associated with adverse h...

Thyroid hormone transporters at the plasma membrane govern intracellular thyroid hormone concentrations. MCT8 represents a key thyroid hormone transporter. MCT8 deficiency (also known as Allan-Herndon-Dudley syndrome) is a devastating developmental disorder caused by mutations in the MCT8 gene (located on the X-chromosome), with an estimated prevalence of 1:70.000 males. The phenotype comprises (1) a &#...

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder, affecting 10–18% of women of reproductive age. Based on the Rotterdam consensus, PCOS is diagnosed by at least two of the following three criteria: oligo- or anovulation, hyperandrogenism, and polycystic ovaries on ultrasound. PCOS is also a metabolic disorder since many affected women present with obesity, insulin resistance and associated metabolic comorbidities. Despite its prevale...

Since thyroid hormone is a key regulator of metabolism, changes in thyroid hormone signaling have widespread effects. Thyroid state changes during aging and vice versa lifespan is affected by thyroid state. However, underlying mechanisms remain elusive. DNA damage importantly contributes to the process of aging, as underscored by premature aging syndromes caused by defective DNA repair.In different mouse models of premature (DNA-repair deficient animals)...

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women in their reproductive age. Based on the Rotterdam criteria PCOS is diagnosed by at least two out of the following three criteria: hyperandrogenism, oligo/anovulation, and polycystic ovaries. To date, the underlying cause of PCOS remains unknown, although the elevated androgen levels are suggested to play an important role in the development of PCOS. In addition to ovarian dysfunction, women with PC...

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...

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder, affecting 10–18% of women of reproductive age. Based on the Rotterdam consensus, PCOS is diagnosed by at least two of the following three criteria: oligo- or anovulation, hyperandrogenism, and polycystic ovaries on ultrasound. Thus, four different phenotypes can be recognized. In addition, PCOS is also a metabolic disorder since many affected women present with obesity, insulin resistance and associa...

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...

Both action and metabolism of thyroid hormone are intracellular events which require the transport of iodothyronines across the plasma membrane. This does not occur by simple diffusion but is facilitated by transport proteins. During the last few years thyroid hormone transporters have been characterized at the molecular level. These include the Na+-taurocholate cotransporting polypeptide (NTCP), different members of the Na+-independent organic anion tran...

Thyroid hormone is essential for the metabolic function of all tissues throughout life and for the development of different organs, notably the brain. Although the thyroid gland mainly secretes T4, most actions of thyroid hormone are initiated by binding of T3 to its nuclear receptor. The biological activity of thyroid hormone in target cells is determined by the intracellular T3 concentration which depends on the circulating levels of T3 and its precursor T4, the activity of ...