Endocrine Abstracts

Ovariectomy of immature female rats, results in significant decreased parameters in different organs. Previously we found that estradiol-17b (E₂) restored these parameters in the different organs of ovariectomized female rats (Ovx) to values obtained in intact immature female rats. E₂ also stimulated creatine kinase specific activity (CK) a hormonal-responsive marker in organs containing estrogen receptors. In the present study, we compared the effects of E₂ to those of the phytoestrogens: quercertin (Qu), daidzein (D), genistein (G), biochainin A (BA) and their carboxy-derivatives cD, cG and cBA in immature and Ovx female rats, on CK in diaphyseal bone (Di) and epiphyseal cartilage (Ep) as well as uterus (Ut) and pituitary (Pi), when injected for 24 h with and without the SERM raloxifene (Ral), or with and without pre-treatment for three days with the less-calcemic vitamin D analog JK 1624F2-2 (JKF). Ovariectomy resulted in significantly reduced CK levels in all organs tested. All estrogenic compounds tested in both age groups stimulated CK. Ral stimulated CK in all organs except Ut but inhibited enzymatic stimulation by E₂ and some of the estrogenic compounds in an age- and organ-specific patterns. Pre-treatment with JKF increased CK response to E₂ and some of the estrogenic compounds in age- and organ-specific patterns. In summary, estrogenic target organs of female rats are modulated differently in an age- and organ-dependent manner in a yet unknown mechanism which might be connected to estrogen receptors in the organs.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.