title: Differential response of type 2 deiodinase gene expression to photoperiod between photoperiodic Fischer 344 and nonphotoperiodic Wistar rats.
abstract: The molecular basis of seasonal or nonseasonal breeding remains unknown. Although laboratory rats are generally regarded as photoperiod-insensitive species, the testicular weight of the Fischer 344 (F344) strain responds to photoperiod. Recently, it was clarified that photoperiodic regulation of type 2 iodothyronine deiodinase (Dio2) in the mediobasal hypothalamus (MBH) is critical in photoperiodic gonadal regulation. Strain-dependent differences in photoperiod sensitivity may now provide the opportunity to address the regulatory mechanism of seasonality by studying Dio2 expression. Therefore, in the present study, we examined the effect of photoperiod on Dio2 expression in photoperiod-sensitive F344 and photoperiod-insensitive Wistar rats. A statistically significant difference was observed between short and long days in terms of testicular weight and Dio2 expression in the F344 strain, while no difference was observed in the Wistar strain. These results suggest that differential responses of the Dio2 gene to photoperiod may determine the strain-dependent differences in photoperiod sensitivity in laboratory rats.
authors.affiliation: Division of Biomodeling, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yasuo
authors.forename: Miwa
authors.initials: M
authors.lastname: Watanabe
authors.forename: Masayuki
authors.initials: M
authors.lastname: Iigo
authors.forename: Takahiro J
authors.initials: TJ
authors.lastname: Nakamura
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takagi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ono
authors.forename: Shizufumi
authors.initials: S
authors.lastname: Ebihara
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007031:Hypothalamus / Q000201:enzymology; D007279:Injections, Subcutaneous; D007453:Iodide Peroxidase / Q000235:genetics* / Q000378:metabolism*; D008027:Light; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology; D009929:Organ Size; D017440:Photoperiod; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D011916:Rats, Inbred F344; D017208:Rats, Wistar; D013045:Species Specificity; D013737:Testis / Q000033:anatomy & histology
chemical_list: D012333:RNA, Messenger; D007453:Iodide Peroxidase; D008550:Melatonin