title: Activity in the ferret:  oestradiol effects and circadian rhythms.
abstract: The present study was conducted to determine whether oestradiol increases activity in the European ferret (Mustela furo), whether this effect is sexually dimorphic, and whether a 24-h rhythm is present in the ferret's daily activity.  The activity of male and female adult, postpubertally gonadectomized ferrets was monitored while they were maintained singly on a 13:11 light-dark cycle, before and after implantation with oestradiol-17 beta.  Gonadectomized male and female ferrets exhibited equal levels of activity, and neither sex exhibited a significant change in activity following oestradiol implantation.  None of the ferrets exhibited a strong circadian rhythm, although weak 24-h rhythms and shorter harmonic rhythms were present.  Golden hamsters (Mesocricetus auratus), monitored in an identical manner, exhibited strong circadian rhythms.  It was concluded that oestradiol administration may not cause an increase in activity in the ferret, and that this species lacks a strong circadian activity rhythm.
authors.affiliation: Department of Nutrition and Food Sciences, Massachusetts Institute of Technology, Cambridge 02139, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Stockman
authors.forename: H E
authors.initials: HE
authors.lastname: Albers
authors.forename: M J
authors.initials: MJ
authors.lastname: Baum
mesh_terms: D000204:Activity Cycles / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002940:Circadian Rhythm / Q000187:drug effects* / Q000502:physiology; D006224:Cricetinae; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005289:Ferrets / Q000502:physiology*; D008297:Male; D008647:Mesocricetus; D009919:Orchiectomy; D010052:Ovariectomy; D012737:Sex Factors
chemical_list: D004343:Drug Implants; D004958:Estradiol