Do estrogen and testosterone use different cellular pathways to inhibit osteoclastogenesis and bone resorption?
Te is likely to have direct and indirect inhibitory effects on human osteoclast formation and bone resorption, whereas the effect of E2 on osteoclast precursors and osteoclasts seems to be mediated by osteoblastic cells. Inhibitory effect of E2 is associated with the stimulated secretion of OPG by osteoblast-derived osteosarcoma cells. Mechanism of action of E2 and Te is mediated by ER and AR, respectively.
We concluded that ATRA induced cellular proliferation of irradiated AFT024 cells and expression of a number of genes whose relevance to HPC homeostasis would have to be further examined.