title: Photostimulation affects gonadotropin-releasing hormone immunoreactivity and activates a distinct neuron population in the hypothalamus of the mallard.
abstract: To reveal central mechanisms that transduce photic stimuli to sexually related neuroendocrine changes, Fra-2-ir, an inducible immediate-early gene marker of neuronal activation has been consecutively localized with that of GnRH-I in the brain of mallards that were triggered by artificial light at the photosensitive phase of the reproductive cycle. Strong neuronal activation was found in the POM and PVN in response to 1x or 4x 20 h light exposure that was accompanied with an increase of GnRH-ir in the hypothalamus and a dramatic depletion of GnRH-ir from terminals in the median eminence. The Fra-2 and GnRH-ir profiles, however, were not co-localized in any region at any phase of photostimulation. These results demonstrate profound changes of GnRH-ir in the hypothalamus and reveal a distinct, photoresponsive cell population in the anterior hypothalamic area of the mallard.
authors.affiliation: Department of Reproductive Biology, University of Agriculture, Gödöllö, Hungary.
authors.forename: P
authors.initials: P
authors.lastname: Péczely
authors.forename: K J
authors.initials: KJ
authors.lastname: Kovács
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism; D004372:Ducks / Q000033:anatomy & histology* / Q000378:metabolism*; D005260:Female; D051921:Fos-Related Antigen-2; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology* / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010775:Photic Stimulation; D012621:Seasons; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D051921:Fos-Related Antigen-2; D014157:Transcription Factors; D007987:Gonadotropin-Releasing Hormone