TGF-BETA-1 MESSENGER-RNA EXPRESSION AND PROLIFERATION OF HUMAN OSTEOBLASTIC CELLS IN NONOSTEOPOROTIC AND OSTEOPOROTIC WOMEN UNDER INFLUENCEOF TGF-BETA-1 AND IGF-I

Currently, primary osteoporosis is the most frequent metabolic disease in women after menopause [1]. The resulting loss of bone mass is acco mpanied by an increased risk of skeletal fragility. One reason for the development of osteoporosis might be an impaired function of mature o steoblasts. To evaluate the involvement of specific growth factors in bone remodeling, cell cultures of osteoblastic cells derived from nono steoporotic and osteoporotic postmenopausal women were established. Th e influences of TGF beta-1 and IGF-I on proliferation and mRNA express ion of TGF beta-1 were investigated by [H-3]-thymidine incorporation a nd competitive RT-PCR. We found IGF-I to have no significant effect on proliferation in cells of osteoporotic and nonosteoporotic patients. In contrast, differences were found in TGF beta-1 mRNA expression afte r application of IGF-I. Application of TGF beta-1 enhanced its own mRN A expression in both groups in a similar manner. Whereas the prolifera tion of cells of nonosteoporotic patients was inhibited by (10(-10) M) TGF beta-1, this treatment led to an increased proliferation of cells of osteoporotic patients.