Advances in TRH signaling

Authors: Patricia JosephBravo Lorraine JaimesHoy JeanLouis Charli

Publish Date: 2016/08/12

Volume: 17, Issue: 4, Pages: 545-558

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Abstract

The activity of the hypothalamuspituitarythyroid axis HPT is coordinated by hypophysiotropic thyrotropin releasing hormone TRH neurons present in the paraventricular nucleus of the hypothalamus Hypophysiotropic TRH neurons act as energy sensors TRH controls the synthesis and release of thyrotropin which activates the synthesis and secretion of thyroid hormones in target tissues transporters and deiodinases control their local availability Thyroid hormones regulate many functions including energy homeostasis This review discusses recent evidence that covers several aspects of TRH role in HPT axis regulation Knowledge about the mechanisms of TRH signaling has steadily increased New transcription factors engaged in TRH gene expression have been identified and advances made on how they interact with signaling pathways and define the dynamics of TRH neurons response to acute and/or longterm influences Albeit yet incomplete the relationship of TRH neurons activity with positive energy balance has emerged The importance of tanycytes as a central relay for the feedback control of the axis as well as for HPT responses to alterations in energy balance and other stimuli has been reinforced Finally some studies have started to shed light on the interference of prenatal and postnatal stress and nutrition on HPT axis programing which have confirmed the axis susceptibility to early insults

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