[Effects of various factors involved in bone metabolism on 45Ca2+ incorporation and alkaline phosphatase activity of ROS 17/2.8 cells].

Abstract

The effects of interleukin 1, transforming growth factor-beta (coupling factors), prostaglandin E1, and prostaglandin E2 on incorporation of 45Ca2+ and on alkaline phosphatase activity were studied using cultured ROS 17/2.8 cells, one of cell lines derived from rat osteosarcoma. We found that all these factors stimulate both the incorporation of 45Ca2+ and alkaline phosphatase activity of these cells. On the other hand, one of the bone resorption hormones, parathyroid hormone (PTH), suppressed the proliferation of cells and decreased the alkaline phosphatase activity at considerably low concentrations (1 X 10(-12)-1 X 10(-11) M). However, the hormone stimulated the incorporation of 45Ca2+ by these cells in a dose-dependent manner; the maximum stimulation on day 3 was observed at 1 X 10(-7) M and it was approximately 3 times the control value. The data suggest therefore, that the osteoblasts incorporated calcium ions and transported them while bone resorption was occurring. Thus the ROS 17/2.8 cell line appears to be an advantageous experimental system for the study of calcium metabolism of osteoblasts in vitro.