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PA Heine1 , DB Lubahn2 *, PS Cooke1 *
Department of Veterinary Biosciences, University of Illinois, Urbana , IL 1
Departments of Biochemistry and Child Health, University of Missouri, Columbia, MO 2
Males and females both express ER in their WAT. Ovariectomy results in increased WAT, presumably due to impaired signaling through ER. Despite the critical role of estrogen and ER in the development and maintenance of WAT in females, it is not known whether estrogen is causing these changes by acting through the classical ER or the recently cloned ER. In addition, although male ER knockout (ERKO) and wild-type mice both have significant concentrations of circulating estradiol, it is unclear if ER plays any role in male WAT. The aim of this study was to quantitate WAT in male wild-type and ERKO mice and to histologically characterize any differences between the two groups. Six-month-old male wild-type and ERKO mice (n=4 and 5, respectively) were weighed and killed. Perirenal, inguinal/femoral and epididymal fat pads were collected, weighed and fixed for histological analysis. Average body weights of ERKO mice were slightly greater than controls. Perirenal, epididymal and inguinal/femoral fat pads weighed approximately 50%, 50% and 30% more, respectively, in ERKOs as compared to wild-type mice. Morphometric analysis of WAT indicated that ERKO epididymal fat pad cells were 20% larger than those of wild-type mice, and the inguinal/femoral and perirenal fat pad cells were both 35% larger in ERKO mice. These results show that ER may play a role in WAT deposition in males and suggest that WAT accumulation in mice lacking ER is due at least in part to hypertrophy of the individual fat cells. It is unclear at this time, however, whether the changes in WAT in males lacking ER result from changes in the adipocytes themselves and/or changes in the neuroendocrine regulation of white adipose tissue.
This abstract is being presented on Tuesday, August 3 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.