Sexual dimorphism in the response of adipose mass and cellularity to graded caloric restriction.
OBJECTIVE
To investigate the effects of mild to moderate caloric restriction on parameters of body growth, fat mass, and adipose tissue cellularity in female and male Wistar rats.


METHODS
Three-month-old female and male Wistar rats were subjected to a chronic, mild to moderate caloric restriction paradigm (5%, 10%, or 20% reduction in caloric intake from ad libitum values) for 6 months. This was accomplished using a unique automated feeder system tailored to the food consumption levels of individual rats. Body weight and length, weight of lean organs, regional adipose mass, and adipose cellularity were measured before and after the diet restriction.


RESULTS
Caloric restriction produced proportional decelerations in body weight increases in both genders, without significant changes in body length or lean organ mass. Marked and disproportional reductions in regional adipose tissue mass were produced at all levels of food restriction (even at 5% restriction). An unexpected finding was that in response to graded caloric restriction, female rats preserved adipose fat cell number at the expense of fat cell volume, whereas the converse was seen for male rats.


CONCLUSIONS
These studies demonstrate a sexual dimorphism in the response to mild to moderate degrees of chronic caloric restriction. At low levels of caloric restriction, it is possible to affect regional adipose mass and cellularity while preserving lean organ mass.
Porter
Marty H
MH
Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia 30309, USA. marty.porter@piedmont.org
Fine
Jacqueline B
JB
Cutchins
Alexis G
AG
Bai
Yaohui
Y
DiGirolamo
Mario
M
D017667:Adipocytes / Q000166:cytology*; D000273:Adipose Tissue / Q000254:growth & development*; D000375:Aging; D000818:Animals; D001699:Biometry; D001835:Body Weight; D002452:Cell Count; D048429:Cell Size; D002149:Energy Intake; D005260:Female; D005508:Food Deprivation; D008297:Male; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D012727:Sex Characteristics