Abstract
The Rice-500 Leydig cell tumor of Fischer rats is associated with humoral hypercalcemia invivo and produces a factor that stimulates cAMP formation in cultured rat osteosarcoma cells. We found that cultured human skin fibroblasts respond to both human PTH-(1–34) and the factor produced by cultured rat Leydig tumor cells with a dose-dependent rise in cAMP formation. The time courses for stimulation of the two agents were similar, and stimulation by both was blocked by the competitive PTH antagonist [8,18-norleucine,34-tyrosine]bovine PTH-(3–34) amide. These data suggest that PTH-like factors secreted by a murine tumor are capable of interacting with the human PTH receptor.(J Clin Endocrinol Metab60: 1144,1985)