Parathyroid hormone-responsive adenylate cyclase in induced transplantable osteogenic rat sarcoma

AN apparent paradox prevents accurate assessment of the role of cyclic AMP in the development and maintenance of tumours. Although cell culture experiments indicate that malignant transformation is associated with decreased adenylate cyclase activity and intracellular cyclic AMP levels 1,2 , the same is not true of in vivo studies with tumours, in which a range of results have been obtained, from low 3 to normal 4 and elevated 5 tumour cell cyclic AMP levels. We report here the development of a transplantable osteogenic sarcoma which has retained through many generations a parathyroid hormone-responsive adenylate cyclase, providing a system which can be used to evaluate the significance of hormone-responsive adenylate cyclase for tumour cell growth and differentiation.