title: Temporal variation in serum nitrite levels in rats and mice.
abstract: Although considerable evidence implicates involvement of nitric oxide (NO) in circadian regulation, little is known about possible 24 h variations in basal NO metabolism. In this study, daily variations in serum nitrite levels were studied in locally bred mice and rats during the months of September and October. The serum was separated from blood samples obtained at six different times of the day and night (1 h, 5 h, 9 h, 13 h, 17 h, and 21 h after lights off [HALO] from male albino mice and rats). As an index of in vivo NO generation, serum nitrite levels (determined by the diazotization method) in rats exhibited significant temporal fluctuation (unpaired Student t test), with the concentration highest at 5 HALO and 21 HALO and lowest at 9 HALO. No such temporal variation was detected in mice in these studies conducted on locally bred animals in the autumn.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Uludağ
authors.forename: B
authors.initials: B
authors.lastname: Tunçtan
authors.forename: H Z
authors.initials: HZ
authors.lastname: Güney
authors.forename: C
authors.initials: C
authors.lastname: Uluoğlu
authors.forename: S
authors.initials: S
authors.lastname: Altuğ
authors.forename: H
authors.initials: H
authors.lastname: Zengil
authors.forename: N
authors.initials: N
authors.lastname: Abacioğlu
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D006152:Cyclic GMP / Q000378:metabolism; D008297:Male; D051379:Mice; D009569:Nitric Oxide / Q000097:blood; D009573:Nitrites / Q000097:blood*; D017440:Photoperiod; D051381:Rats; D012621:Seasons; D015398:Signal Transduction; D013493:Suprachiasmatic Nucleus / Q000502:physiology
chemical_list: D009573:Nitrites; D009569:Nitric Oxide; D006152:Cyclic GMP