Melatonin receptors in the suprachiasmatic nuclei and pars tuberalis of testosterone induced photoresponsive rats.
The sexual axis of rats can be rendered photoresponsive by testosterone implants. We have studied in these conditions whether rat pars tuberalis (PT) melatonin receptor density would be decreased after exposure to short photoperiod (SP) like as observed in long day seasonal breeders. The answer is no, but we observed that testosterone induced a photoperiod independent decrease in PT melatonin receptor density. These results show that testosterone-induced photosensitivity in rat is not linked to an SP-induced decrease in PT melatonin receptor density. However, testosterone regulates PT melatonin receptors independently of the photoperiod.
Recio
J
J
Neurobiologie des Fonctions Rythmiques et Saisonnières, URA-CNRS 1332, Université Louis Pasteur, Strasbourg, France.
Pévet
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P
Míguez
J M
JM
Masson-Pévet
M
M
D000818:Animals; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism; D017440:Photoperiod; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D051381:Rats; D017208:Rats, Wistar; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D044094:Receptors, Melatonin; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D013739:Testosterone / Q000494:pharmacology*
D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D044094:Receptors, Melatonin; D013739:Testosterone; D008550:Melatonin