title: Photoperiod regulation of mineralocorticoid receptor mRNA expression in hamster hippocampus.
abstract: Hippocampal mineralocorticoid receptor mRNA expression was increased in male hamsters exposed to 18 days of short photoperiod relative to animals maintained under long day illumination (p < 0.05). Short day hamsters were also characterized by increased weight gain, and heavier adrenal glands (p < 0.05). The larger adrenals showed selective increases in the widths of the zonae reticularis and glomerulosa (p < 0.001). Incidences of torpor and reduced body temperature were observed in the short day animals. No changes were found in reproductive organ weights, systolic blood pressure, open-field behavior, or stress levels of plasma corticosteroids. We conclude that the hamster brain-adrenal axis responds rapidly to changes in photoperiod, raising the possibility that this axis is a primary mediator of shortened photoperiod responses.
authors.affiliation: Department of Physiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614-70756, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Lance
authors.forename: S C
authors.initials: SC
authors.lastname: Miller
authors.forename: L I
authors.initials: LI
authors.lastname: Holtsclaw
authors.forename: B B
authors.initials: BB
authors.lastname: Turner
mesh_terms: D000305:Adrenal Cortex Hormones / Q000097:blood; D000818:Animals; D006224:Cricetinae; D004435:Eating; D015870:Gene Expression / Q000502:physiology*; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008647:Mesocricetus; D009929:Organ Size; D017440:Photoperiod; D010913:Pituitary-Adrenal System / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018161:Receptors, Mineralocorticoid / Q000235:genetics*
chemical_list: D000305:Adrenal Cortex Hormones; D012333:RNA, Messenger; D018161:Receptors, Mineralocorticoid