Bone cells (human and bovine) have been utilized to 1) study the responsiveness of the cells to a variety of hormonal and pharmacological factors such as parathyroid hormone and 1,25 dihydroxy vitamin D3, 2) to study the biosynthesis of extracellular matrix proteins such as collagen, osteonectin and bone proteoglycan, and alterations of matrix production in the disease Osteogenesis Imperfecta, 3) to serve as a source of mRNA and DNA for studies of these proteins at the genomic level.