A limited understanding of the physiological relationships between TSH and thyroid hormones may be a main reason for clinical difficulties in dealing with the causes of syndrome T and tailoring substitution therapy for hypothyroid patients with subclinical thyroid disorders.
Feedback regulation has recently been shown to be much more complex than previously assumed. The concept of homeostatic control has also been extended to include the lesser known but equally important allostatic thyroid regulation.The latter aims at adaptive homeostasis or stability through changing setpoints and modulating structural parameters of feedback control, as may be appropriate to adapt to a vast array of conditions spanning from fetal life, aging, pregnancy, exercise, starvation, obesity, psychiatric disorders to the severe non-thyroidal illness syndrome.
A better understanding of homeostatic and allostatic mechanisms, which govern the behaviour of pituitary-thyroid feedback control, is on the horizon. This promises to improve the diagnostic utility of laboratory methods, laying the foundation for personalised methods to optimise dosage and modality of substitution therapy. The emerging new world of thyroid physiology is reflected on the side of clinical medicine in a new, relational paradigm for diagnosis and treatment.
Considerable progress has been made in this respect in the following key areas:
? the significance of complementary information processing structures within the feedback loop, in particular ultrashort feedback of TSH on its own secretion and the action of a TSH-T3 shunt unburdening the thyroid from T4 synthesis in imminent thyroid failure,
? the unravelling of spatio-temporal dynamics of hormone concentrations ranging from ultradian to circannual rhythms and including hysteresis effects,
? the emergence of "non-canonical" mechanisms of thyroid hormone signalling beyond transcriptional control of gene expression,
? the physiological actions of thyronine metabolites, which have been previously regarded as biologically inactive, such as thyronamines and iodothyroacetates,
? the characterisation of distinct patterns in the adaptive processes to stress and strain and their conclusive explanation through reactions to type 1 and type 2 allostatic load.
This collective volume contains the contributions to the Research Topic "Homeostasis and Allostasis of Thyroid Function", which was originally published by the journal Frontiers in Endocrinology. Authored by an international team of experts from three continents ,the book provides a comprehensive overview on thyroid control from recent research in basic, computational and clinical thyroidology. Many aspects addressed here can be expected to stimulate future research. A more comprehensive view and better integration of in-vitro, in-silico and in-vivo investigations will be invaluable in paving the way to this new world of thyroidology. 606 $aMedicine and Nursing$2bicssc 610 $a3-T1AM 610 $aHypothyroidism 610 $aHysteresis 610 $aprecision medicine 610 $arelational stability 610 $aStratified Medicine 610 $athyroid allostasis 610 $aThyroid homeostasis 610 $aThyronamines 610 $aTSH-T3 Shunt 615 7$aMedicine and Nursing 700 $aRudolf Hoermann$4auth$01325061 702 $aJohn E. M. Midgley$4auth 702 $aJohannes W. Dietrich$4auth 906 $aBOOK 912 $a9910346752303321 996 $aHomeostasis and Allostasis of Thyroid Function$93036530 997 $aUNINA