The effects of native and synthetic estrogenic compounds as well as vitamin D less-calcemic analogs on adipocytes content in rat bone marrow

Background: We demonstrated previously that phytoestrogens and vitamin D analogs like estradiol-17 beta (E-2) modulate bone morphology in rat female model. Aim: We now analyze the effects of phytoestrogens, E2, selective E-2 receptor modulators, and the less-calcemic analogs of vitamin D: JKF1624F(2)-2 (JKF) or QW1624F(2)-2 (QW) on fat content in bone marrow (BM) from long bones in ovariectomized female rats (OVX). Materials and methods: OVX rats were injected with treatments known to affect bone formation, 5 days per week for 2.5 month for analysis of fat content in BM. Results: In OVX young adults there is a decreased bone formation and a 10-fold increase in fat cells content in BM. Treatment with E-2, raloxifene (Ral) or DT56a resulted in almost completely abolishment of fat cells content. Daidzein (D) decreased fat cells content by 80%, genistein (G) or biochainin A (BA) did not change fat cells content and carboxy BA (cBA) had a small but significant effect. JKF or QW did not affect fat cells content, whereas combined treatment of JKF or QW with E-2 resulted in complete abolishment of fat cells content. These changes in fat cells content are inversely correlated with changes in bone formation. Conclusions: Our results demonstrate that adipogenesis induced by OVX is a reversible process which can be corrected by hormonal treatments. The awareness of a relationship between fat and bone at the marrow level might provide a better understanding of the pathophysiology of bone loss as well as a novel approach to diagnosis and treatment of postmenopausal osteoporosis. (J. Endocrinol. Invest. 34: 106-110, 2011) (C)2011, Editrice Kurtis