| Abstract
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Clinical observations in primary hyperparathyroidism, corticosteroid-induced osteoporosis, and in osteoporotic patients treated with fluoride, progesterone or estrogen, suggest that different skeletal sites respond differently in various disease states and to their treatments. We hypothesized that these different response patterns could be based, at least in part, on differences in the properties on the populations of cells in these different sites. Cell populations derived from vertebral, femoral cancellous, femoral cortical and calvarial bone tissue were characterized histochemically by staining for alkaline phosphatase, tartrate-resistant acid phosphatase, Sudan IV, Alcian blue and usd\alphausd-napthylbutyrate esterase activity. Analysis of the cells subcultured from explants cultured for 14-16 days showed that, when compared to calvarial populations, the absolute cyclic adenosine monophosphate response to parathyroid hormone was 1/3 lower in vertebral, 2/3 lower in femoral cancellous and 1/3 lower in femoral cortical populations. The parathyroid hormone response was found to be lower than the prostaglandin E2 response in calvarial and femoral cancellous populations, but slightly higher in vertebral and femoral cortical populations. In addition, we analyzed and characterized the osteoprogenitors in these populations using a colony assay for osteoprogenitors previously developed for fetal rat calvarial cell populations (Bellows et al., 1986). The results show that cells isolated for explants cultured for 14-16 days from vertebral, femoral cancellous, calvarial and to a much lesser extent femoral cortical populations contain osteoprogenitors that differentiate to form bone modules in the presence of dexamethasone. Progenitors forming bone nodules in response to progesterone were most numerous in vertebral cells and calvarial populations, were detected in lower numbers in femoral cancellous populations and were infrequent in femoral cortical populations. The parathyroid hormone induced cyclic adenosine monophosphate response in calvarial and femoral cancellous day 22-24 cultures increased relative to day 14-16 derived cultures. (Abstract shortened by UMI.)
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