EXPRESSION OF EXTRACELLULAR CALCIUM (CA-O(2-SENSING RECEPTOR IN THE CLONAL OSTEOBLAST-LIKE CELL-LINES, UMR-106 AND SAOS-2()))

The calcium-sensing receptor (CaR) is a G protein-coupled receptor tha t plays key roles in extracellular calcium ion (Ca-o(2+)) homeostasis in parathyroid gland and kidney. More recent data have suggested the p resence of this receptor in additional tissues, such as brain, intesti ne and skin. In this study, we examined the expression of the CaR in t he rat and human osteosarcoma cell lines, UMR-106 and SAOS-2, respecti vely, which possess osteoblast-like characteristics. Both immunocytoch emistry and Western blot analysis, using a polyclonal antiserum specif ic for the CaR, detected CaR protein in UMR-106 and SAOS-2 cells. The use of reverse transcription-polymerase chain reaction (RT-PCR) with C aR-specific primers, followed by nucleotide sequencing of the amplifie d products, also identified CaR transcripts in each cell line. Therefo re, taken together, our data strongly suggest that the osteoblast-like cell lines, UMR-106 and SAOS-2, possess both CaR protein and mRNA ver y similar if not identical to those in parathyroid and kidney. (C) 199 8 Academic Press.