title: Melatonin in the plasma of growing sheep subjected to short and skeleton long photoperiods.
abstract: The levels of melatonin in plasma were measured at hourly intervals for 24 h in 8 sheep, 4 under 8L:16D (short day) and 4 under 7L:10D:1L:6D (skeleton long day) after 38 days of exposure. Mean concentrations did not differ significantly between treatments (52 pg/ml under short days; 91 pg/ml for skeleton long days), but the levels were more stable during 24 h in the SD treatment. Under skeleton long days there were 3 peaks during the 10D scotophase, with low levels during the 6D scotophase and the 7L photophase.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D008027:Light; D008297:Male; D008550:Melatonin / Q000097:blood*; D010507:Periodicity; D010870:Pineal Gland / Q000502:physiology; D011388:Prolactin / Q000097:blood; D012756:Sheep / Q000502:physiology*
chemical_list: D011388:Prolactin; D008550:Melatonin; D006854:Hydrocortisone