Blar i forfatter "Dardente, Hugues"

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    • Anti-angiogenic VEGFAxxxb transcripts are not expressed in the medio-basal hypothalamus of the seasonal sheep 

      Lomet, Didier; Piegu, Benoit; Wood, Shona Hiedi; Dardente, Hugues (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-10)
      This study investigated Vegfa expression in the pars tuberalis (PT) of the pituitary and medio-basal hypothalamus (MBH) of sheep, across seasons and reproductive states. It has recently been proposed that season impacts alternative splicing of Vegfa mRNA in the PT, which shifts the balance between angiogenic VEGFAxxx and anti-angiogenic VEGFAxxxb isoforms (with xxx the number of amino acids of the ...

    • Circuit-level analysis identifies target genes of sex steroids in ewe seasonal breeding 

      Lomet, Didier; Druart, Xavier; Hazlerigg, David; Beltramo, Massimiliano; Dardente, Hugues (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-15)
      Thyroid hormone (TH) and estradiol (E2) direct seasonal switches in ovine reproductive physiology. In sheep, as in other mammals and birds, control of thyrotropin (TSH) production by the pars tuberalis (PT) links photoperiod responsiveness to seasonal breeding. PT-derived TSH governs opposite seasonal patterns of the TH deiodinases Dio2/Dio3 expression in tanycytes of the neighboring medio-basal ...

    • Discontinuity in the molecular neuroendocrine response to increasing daylengths in Ile-de-France ewes: Is transient Dio2 induction a key feature of circannual timing? 

      Dardente, Hugues; Lomet, Didier; Chesneau, Didier; Pellicer-Rubio, Maria-Teresa; Hazlerigg, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-24)
      In mammals, melatonin is responsible for the synchronisation of seasonal cycles to the solar year. Melatonin is secreted by the pineal gland with a profile reflecting the duration of the night and acts via the pituitary pars tuberalis (PT), which in turn modulates hypothalamic thyroid hormone status via seasonal changes in the production of locally‐acting thyrotrophin. Recently, we demonstrated that, ...

    • Effects of photoperiod extension on clock gene and neuropeptide RNA expression in the SCN of the Soay Sheep 

      Dardente, Hugues; Wyse, Cathy A.; Lincoln, Gerald A.; Wagner, Gabriela; Hazlerigg, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      In mammals, changing daylength (photoperiod) is the main synchronizer of seasonal functions. The photoperiodic information is transmitted through the retino-hypothalamic tract to the suprachiasmatic nuclei (SCN), site of the master circadian clock. To investigate effects of day length change on the sheep SCN, we used in-situ hybridization to assess the daily temporal organization of expression of ...

    • An integrative view of mammalian seasonal neuroendocrinology 

      Dardente, Hugues; Wood, Shona Hiedi; Ebling, Francis; Sáenz de Miera, Cristina (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-06)
      Seasonal neuroendocrine cycles that govern annual changes in reproductive activity, energy metabolism and hair growth are almost ubiquitous in mammals that have evolved at temperate and polar latitudes. Changes in nocturnal melatonin secretion regulating gene expression in the pars tuberalis (PT) of the pituitary stalk are a critical common feature in seasonal mammals. The PT sends signal(s) to the ...

    • Photoperiodic induction without light-mediated circadian entrainment in a High Arctic resident bird 

      Appenroth, Daniel; Melum, Vebjørn Jacobsen; West, Alexander Christopher; Dardente, Hugues; Hazlerigg, David; Wagner, Gabriela (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-21)
      Organisms use changes in photoperiod to anticipate and exploit favourable conditions in a seasonal environment. While species living at temperate latitudes receive day length information as a year-round input, species living in the Arctic may spend as much as two-thirds of the year without experiencing dawn or dusk. This suggests that specialised mechanisms may be required to maintain seasonal ...

    • Thyroid hormone and seasonal rhythmicity 

      Dardente, Hugues; Hazlerigg, David; Ebling, Francis J.P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-02-26)
      Living organisms show seasonality in a wide array of functions such as reproduction, fattening, hibernation, and migration. At temperate latitudes, changes in photoperiod maintain the alignment of annual rhythms with predictable changes in the environment.The appropriate physiological response to changing photoperiod in mammals requires retinal detection of light and pineal secretion of melatonin, ...