Shamay, A., Institute of Animal Science, ARO, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Knopov, V., Institute of Animal Science, ARO, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Benayahu, D., Dept. of Cell Biology and Histology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv 66978, Israel

MBA-15, a marrow stromal-derived cell line, was shown to express an estrogen receptor. This finding was confirmed by in situ hybridization and receptor binding assay. An exposure to estrogen (10-12-10-6M) in a dose response manner resulted in a decrease of cell proliferation as measured by MTT assay. Cell function was measured by enzymatic activities of two osteoblastic markers, CD1O/NEP and alkaline phosphatase. These enzymatic activities were elevated following the estrogen treatment. This model enabled direct evaluation of the estrogen effect on stroma osteoblast cells.