The effect of indomethacin and aspirin on alkaline phosphatase secretion and [3H]thymidine incorporation by human osteoblasts.

Since it has been suggested that long-term treatment with indomethacin and other non-steroidal anti-inflammatory drugs (NSAIDs) may result in destructive changes in the hip joint, we have examined the effect of indomethacin and aspirin on the secretory and mitotic activity of human osteoblasts in culture. Both indomethacin and aspirin inhibited the secretion of alkaline phosphatase and the uptake of [3H]thymidine by osteoblasts in a dose-dependent fashion at therapeutic concentrations. Both drugs also inhibited insulin- and 1,25-dihydroxycholecalciferol-stimulated alkaline phosphatase production and [3H]thymidine uptake by human osteoblasts. It is concluded that indomethacin and aspirin, and possibly other NSAIDs, may have an inhibitory effect on osteoblast function.