Effects of weight loss on bone mineral density in rats.
OBJECTIVE
To evaluate the effects of weight loss on bone mineral density (BMD).


METHODS
Eight-week-old female rats were divided into 4 groups: Those in Group A received a restricted diet for 4 weeks; those in Group B received a restricted diet and were treated with estrogen; those in Group C were castrated; and those in Group D underwent sham operations. The rat's body weight (BW) and vaginal smears were checked, and their femoral BMD was measured.


RESULTS
The BW and BMD at 12 weeks were lower in Groups A and B than in Groups C and D; thereafter, however, these values increased for Groups A and B, but were still lower than those in Group D even at 20 weeks. In Group C, the BMD did not decrease, but it was significantly lower than that in Group D at 16 and 20 weeks. Group A showed continuous diestrus 2 weeks after dietary restriction began, but recovered to a 4-day cycle 2 weeks after the initiation of free food consumption.


CONCLUSIONS
Weight loss had a greater effect on BMD than hypoestrogenism.
Douchi
T
T
Department of Obstetrics and Gynecology, Faculty of Medicine, Kagoshima University, Japan.
Oki
T
T
Kosha
S
S
Nakamura
S
S
Ijuin
H
H
Yamamoto
S
S
Noguchi
S
S
Nagata
Y
Y
D000818:Animals; D015519:Bone Density; D004967:Estrogens / Q000502:physiology; D005260:Female; D010053:Ovary / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015431:Weight Loss
D004967:Estrogens