Thyroid hormone and seasonal rhythmicity

[helvella]

This paper is unlikely to be of specific help to anyone - but hopefully will be of interest to someone! It talks about birds and mammals rather than humans.

Lest anyone suggest that thyroid is simple, this is yet another set of complexities.

REVIEW ARTICLE

published: 26 February 2014

doi: 10.3389/fendo.2014.00019

Thyroid hormone and seasonal rhythmicity

Hugues Dardente 1,2,3,4

*, David G. Hazlerigg 5

and Francis J. P. Ebling 6

1 Physiologie de la Reproduction et des Comportements, INRA, UMR085, Nouzilly, France

2 CNRS, UMR7247, Nouzilly, France

3 Université François Rabelais de Tours, Tours, France

4 Institut français du cheval et de l’équitation, Nouzilly, France

5 Department of Arctic and Marine Biology, University of Tromsø, Tromsø, Norway

6 School of Life Sciences, University of Nottingham, Nottingham, UK

Edited by:

Frédéric Flamant, Ecole Normale

Supérieure de Lyon, France

Reviewed by:

Valerie Simonneaux, Centre National

de la Recherche Scientifique, France

Sulay Tovar, University of Cologne,

Germany

*Correspondence:

Hugues Dardente, INRA, UMR85

Physiologie de la Reproduction et des

Comportements, CNRS, UMR7247,

Université François Rabelais de Tours,

IFCE, F-37380 Nouzilly, France

e-mail: [e-mail]

Living organisms show seasonality in a wide array of functions such as reproduction, fatten-

ing, hibernation, and migration. At temperate latitudes, changes in photoperiod maintain

the alignment of annual rhythms with predictable changes in the environment.The appropri-

ate physiological response to changing photoperiod in mammals requires retinal detection

of light and pineal secretion of melatonin, but extraretinal detection of light occurs in birds.

A common mechanism across all vertebrates is that these photoperiod-regulated systems

alter hypothalamic thyroid hormone (TH) conversion. Here, we review the evidence that a

circadian clock within the pars tuberalis of the adenohypophysis links photoperiod decod-

ing to local changes of TH signaling within the medio-basal hypothalamus (MBH) through

a conserved thyrotropin/deiodinase axis. We also focus on recent findings which indicate

that, beyond the photoperiodic control of its conversion,TH might also be involved in longer-

term timing processes of seasonal programs. Finally, we examine the potential implication

of kisspeptin and RFRP3, two RF-amide peptides expressed within the MBH, in seasonal

rhythmicity.

Full paper freely available here:

researchgate.net/profile/Fr...

[Treepie]

I am sure it is interesting if I could understand the terminology. Bird migration is incredible and fascinating. Some species seem to have to learn the routes following the flocks. Others are hatched and left behind to find there own way.

[Clutter]

Helvella, I think it would be easier to read in medieval French! The article on thyroid function changing to enable salmon to move from fresh to salt water was more interesting.

[helvella Administrator in reply to Clutter]

Fay ce que vouldras. This does have some pictures to make it easier.

[Spareribs]

"Living organisms show seasonality in a wide array of functions such as reproduction, fatten-ing, hibernation, and migration..."

Sunshine!

[helvella Administrator in reply to Spareribs]

Absolutely. Day-length seems to be very important in lots of ways.

Perhaps our artificially lit world is a part of the cause of thyroid issues?

[Spareribs in reply to helvella]

and night shifts, world of Warcraft etc.. together with sunglasses, hats, even clothes? and not eating enough fish up north!