Effect of neonatal exposure to diethylstilbestrol and tamoxifen on pelvis and femur in male mice.
BACKGROUND
Permanent abnormalities have been reported in reproductive and non-reproductive organs of mice and humans exposed perinatally to a synthetic estrogen, diethylstilbestrol (DES). Recent studies demonstrated that sex hormones affected the shape of the innominate bone in mice. Therefore, we analyzed the long-term effects of neonatal exposure of DES and tamoxifen, an anti-estrogen, in mouse bones.


METHODS
Changes in the pelvis and femur were examined in 1- to 15-month-old C57BL/Tw male mice given 5 daily injections of 3 micrograms DES or of 100 micrograms tamoxifen beginning on the day of birth by measuring contents of calcium (Ca) and phosphorus (P), and the numbers of osteoblasts and osteoclasts.


RESULTS
The ash weight of pelvis and femur in neonatally DES- and tamoxifen-treated mice was lower than that in the controls at 2-15 months of age. Contents of Ca and P of pelvis and femur in neonatally tamoxifen-treated mice were lower than in the controls and neonatally DES-treated mice. In neonatally DES-treated mice at 6-12 months, Ca and P contents in the pelvis were lower than in controls, but not different in the femur. The number of osteoblasts per unit length of endocortical surface of the femur in 2- and 3-month-old DES- and tamoxifen-treated mice was lower than that in the controls. The osteoclast number in the femur in DES-treated mice at 2 to 12 months was not different from that in the controls; however, in tamoxifen-treated mice, the number was higher than in the controls. An epiphyseal line was clearly detected in the femur of 12- and 15-month-old DES- and tamoxifen-treated male mice, whereas the line in the controls disappeared after 12 months.


CONCLUSIONS
The present results indicate that in male mice, neonatal exposure to DES and tamoxifen induced permanent changes in the pelvis and the femur, and that tamoxifen had a greater effect on bone tissue than did DES.
Fukazawa
Y
Y
Department of Biology, Yokohama City University, Japan.
Nobata
S
S
Katoh
M
M
Tanaka
M
M
Kobayashi
S
S
Ohta
Y
Y
Hayashi
Y
Y
Iguchi
T
T
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D015519:Bone Density / Q000187:drug effects; D004054:Diethylstilbestrol / Q000008:administration & dosage / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D004968:Estrogens, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D005269:Femur / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010384:Pelvic Bones / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D013629:Tamoxifen / Q000008:administration & dosage / Q000494:pharmacology*; D013739:Testosterone / Q000097:blood
D004965:Estrogen Antagonists; D004968:Estrogens, Non-Steroidal; D013629:Tamoxifen; D013739:Testosterone; D004054:Diethylstilbestrol