期刊
JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY
卷 86, 期 2, 页码 179-188出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0960-0760(03)00270-X
关键词
silymarin; rat; estrogen receptor; LH; lipids; uterus; metaphysis of femur
Silymarin is a widely used standardized mixture of flavonolignans and its major component Silybinin binds to cytosolic estrogen receptors. Here, we demonstrate that this binding is exclusive to the estrogen receptor beta (ERbeta). Treatment of ovariectomized (ovx) rats with silymarin or estradiol (E-2) may allow differentiation of biological effects mediated by the ERalpha or ERbeta. E-2 inhibited serum LH, cholesterol, LDL and HDL concentrations in the blood and increased gene expression of IGF1, HbEGF and C3 in the uterus, while silymarin was totally ineffective or antagonistic in altering these parameters. Both, E-2 and silymarin inhibited expression of uterine ERbeta gene. Hence, in the pituitary, liver (where the lipoproteins are synthesized) and uterus E-2 acts primarily via the ERalpha. Exclusive estrogenic effects of silymarin were observed in the metaphysis of the femur (W), on osteoblast parameters (gene expression of IGF1, TGFbeta1, osteoprotegerin, collagen-1alpha1, osteocalcin (OC)) and on the osteoclast activity marker tartrate resistant acid phosphatase (TRAP) gene expression of adult ovx rats. Our RT-PCR method detects ERbeta gene expression in all organs including developing bones but not in the ME of adult ovx rats. We conclude therefore, that the effects of silymarin in this part of the bone cannot be exerted via the ERalpha because it does not bind to this receptor subtype. Despite the failure to detect ERbeta mRNA in the MF of our animals the possibility exists that ERbeta protein is present and may mediate the effects of silymarin. Another possibility may be that the effect of silymarin and therefore possibly also of E-2 in the MF may be mediated via other possibly not yet identified receptors or via an ERbeta splice variant which is not detected by our PCR-method. (C) 2003 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据