Differential susceptibility to obesity between male, female and ovariectomized female mice.
BACKGROUND
The prevalence of obesity has increased dramatically. A direct comparison in the predisposition to obesity between males, premenopausal females, and postmenopausal females with various caloric intakes has not been made. To determine the effects of sex and ovarian hormones on the susceptibility to obesity, we conducted laboratory studies with mice. To eliminate confounders that can alter body weight gain, such as age and food consumption; we used mice with the same age and controlled the amount of calories they consumed.


METHODS
We determined sex-specific susceptibility to obesity between male, non-ovariectomized female, and ovariectomized female mice. To compare susceptibility to gaining body weight between males and females, animals from each sex were exposed to either a 30% calorie-restricted, low-fat (5% fat), or high-fat (35% fat) diet regimen. To establish the role of ovarian hormones in weight gain, the ovaries were surgically removed from additional female mice, and then were exposed to the diets described above. Percent body fat and percent lean mass in the mice were determined by dual energy x-ray absorptiometry (DEXA).


RESULTS
In all three diet categories, male mice had a greater propensity of gaining body weight than female mice. However, ovariectomy eliminated the protection of female mice to gaining weight; in fact, ovariectomized female mice mimicked male mice in their susceptibility to weight gain. In summary, results show that male mice are more likely to become obese than female mice and that the protection against obesity in female mice is eliminated by ovariectomy.


CONCLUSIONS
Understanding metabolic differences between males and females may allow the discovery of better preventive and treatment strategies for diseases associated with body weight such as cancer and cardiovascular disease.
Hong
Jina
J
Department of Nutritional Sciences, University of Texas at Austin, Austin, TX, USA. j_hong@mail.utexas.edu
Stubbins
Renee E
RE
Smith
Rebekah R
RR
Harvey
Alison E
AE
Núñez
Nomelí P
NP
D015502:Absorptiometry, Photon; D000818:Animals; D004041:Dietary Fats / Q000008:administration & dosage*; D004198:Disease Susceptibility / Q000503:physiopathology; D002149:Energy Intake; D005260:Female; D042341:Gonadal Hormones / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000378:metabolism / Q000517:prevention & control*; D010052:Ovariectomy; D012737:Sex Factors; D015430:Weight Gain
D004041:Dietary Fats; D042341:Gonadal Hormones