The effect of ovarian steroids and photoperiod on body fat stores and uncoupling protein 2 in the marsupial Sminthopsis crassicaudata

Perdita J. Hope, Helen Turnbull, William Breed, John E. Morley, Michael Horowitz, Gary A. Wittert

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8 Citations (Scopus)


To determine the effects of photoperiod and ovarian steroids on fat stores in the marsupial S. crassicaudata, animals were ovariectomised (OVX) or sham operated, and maintained under either short-day (SD) or long-day (LD) photoperiods for 104 days. Photoperiod had no effect on body weight in the sham animals. In the LD OVX animals, body weight fell and remained below baseline for about 45 days, whereafter it returned to baseline. In contrast, body weight of SD OVX animals increased over the first 45 days then returned to baseline. Tail width (a reflection of body fat stores) increased in both sham and OVX animals exposed to SD. When exposed to LD, tail width increased only in the OVX animals. There was no effect of either photoperiod or OVX on total cumulative energy intake. Leptin mRNA expression was increased in the LD OVX animals compared to the shams. Photoperiod had no effect on UCP2 mRNA expression in any tissue; however, OVX decreased UCP2 mRNA expression in muscle. These data indicate that in S. crassicaudata: (a) fat mass increases in response to both SD photoperiod and OVX and they have additive effects; (b) the effects of photoperiod on fat mass are mediated by both gonadal steroid dependent and independent mechanisms; (c) alterations in UCP2 mRNA expression may mediate the effect of OVX, but not photoperiod; and (d) UCP2 mRNA is differentially regulated in muscle and fat. Copyright (C) 2000 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)463-470
Number of pages8
JournalPhysiology and Behavior
Issue number4-5
Publication statusPublished or Issued - 1 Jun 2000


  • Activity
  • Adipose tissue
  • Leptin
  • Marsupial
  • Metabolic efficiency
  • Nutrient partitioning
  • Ovariectomy
  • Photoperiod
  • UCP2

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience

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