Effect of estrogen on gene expression of fatty acid synthase in periosteum.

Background: Estrogen deficiency contributes to postmenopausal osteoporosis. Periosteum might be a potential target of estrogen, but the underlying mechanism at gene level is far from being elucidated. The objective of this study was to investigate the correlation between estrogen and fatty acid synthase (FAS) expression in periosteum.

Methods: Human periosteum cells were cultured in vitro. Expressed genes in the substrated cDNA library were verified using semi-quantitative PCR and real-time PCR. The expression of FAS in periosteum of ovarectomized (OVX) SD rats was investigated.

Results: FAS gene was most significantly expressed in the subtracted cDNA library of periosteal cells screened by semi-quantitative PCR. Low FAS expression was verified by real-time PCR in the estrogen exposed human periosteum rather than in the control. The estradiol levels were (20.81 +/- 12.62) pg/ml, (19.64 +/- 4.35) pg/ml and (13.47 +/- 1.84) pg/ml in the sham group, the control, and the OVX group, respectively. The estradiol levels in the OVX group was significantly lower (P = 0.0386). The FAS gene expression in periosteum in the OVX group, sham group, and control group was 3.09 +/- 1.97, 1.33 +/- 0.47 and 1.51 +/- 1.32, respectively. The gene expression in the OVX group was significantly higher (P = 0.0372).

Conclusion: Estrogen modulates FAS gene expression in in vitro human perisoteum as well as in in vivo rat periosteum.