Increased cortical bone mineral content but unchanged trabecular bone mineral density in female ERbeta(-/-) mice.

• Ovariectomy in young, growing rodents results in decreased trabecular bone mineral density (BMD) and increased radial growth of the cortical bone. Both of these effects are reversed by treatment with estrogen. The aim of the present study was to determine the physiological role of estrogen receptor-beta (ERbeta) on bone structure and bone mineral content (BMC). The BMC was increased in adult (11 weeks old), but not prepubertal (4 weeks old), female ERbeta(-/-) mice compared with wild-type (WT) mice. This increase in BMC in females was not due to increased trabecular BMD, but to an increased cross-sectional cortical bone area associated with a radial bone growth. Male ERbeta(-/-) mice displayed no bone abnormalities compared with WT mice. Ovariectomy decreased the trabecular BMD to the same extent in adult female ERbeta(-/-) mice as in WT mice. The expression levels of osteoblast-associated genes - alpha1(I) collagen, alkaline phosphatase, and osteocalcin mRNAs - were elevated in bone from adult ERbeta(-/-) females compared with WT mice. These observations provide a possible explanation for the increased radial bone growth seen in female mutants, suggesting a repressive function for ERbeta in the regulation of bone growth during female adolescence. In summary, ERbeta is essential for the pubertal feminization of the cortical bone in female mice but is not required for the protective effect of estrogens on trabecular BMD.

Nyckelord

Aging

Alkaline Phosphatase

genetics

Animals

Body Weight

Bone Density

physiology

Bone Development

CD40 Ligand

Collagen

genetics

Estrogen Receptor beta

Female

Femur

growth & development

Gene Expression Regulation

Developmental

Growth Plate

growth & development

Male

Membrane Glycoproteins

genetics

Mice

Mice

Knockout

Ovariectomy

Receptors

Estrogen

deficiency

genetics

physiology

Reverse Transcriptase Polymerase Chain Reaction

Sex Characteristics

Sexual Maturation

Tibia

growth & development

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)