Local mediators of bone resorption may be involved in bone loss in recently postmenopausal women and in osteoporosis. In the present study, we investigated the production of cytokines and the formation of osteoclast-like cells in marrow cultures from 16 late postmenopausal nonosteoporotic women (mean age: 66 +/- 8 years; time after menopause: 15 +/- 8 years) undergoing hip replacement for arthrosis. Marrow adherent mononuclear cells (MMNC) isolated from femoral diaphysis marrow were cultured for 10 days in the absence or in the presence of 1,25(OH)2D3. In vivo bone resorption was concomitantly assessed by histomorphometry on femoral neck bone sections. The number of TRAP+ multinucleated cells obtained after 10 days in MMNC cultured in the presence of 1,25(OH)2D3 correlated with the number of osteoclasts measured on the bone femoral neck biopsies (r = 0.65, p < 0.01), suggesting that the formation of multinucleated cells in vitro could reflect the osteoclast differentiation in vivo. Furthermore, the number of osteoclasts was related to the eroded volume and the trabecular separation of the femoral neck bone biopsies. Finally, the release of interleukin-1 (IL-1), IL-6, and TNF-alpha by cultures of peripheral blood mononuclear cells (PBMC) and MMNC was measured by radioimmunoassay. The cytokine levels of basal and 1,25(OH)2D3-treated MMNC decreased from days 2 to 5 and then reached a plateau to day 10. The number of TRAP+ multinucleated cells obtained after 10 days in MMNC cultures correlated with the basal IL-6 release in the same cultures determined at day 2 (r = 0.55, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)