PRIMARY CULTURES OF HUMAN BONE-DERIVED CELLS PRODUCE PARATHYROID HORMONE-RELATED PROTEIN - A STUDY OF 40 PATIENTS OF VARYING AGE AND PATHOLOGY

Parathyroid hormone-related protein (PTHrP), a mediator of hypercalcem ia of malignancy, has been detected in many tumours and in some normal foetal and adult tissues. PTHrP has potent effects on bone turnover i n vivo and in vitro. In this study we cultured cells derived from expl ants of bone obtained from 40 subjects (age range 2-88 years). Immunor eactive PTHrP (iPTHrP) was detected by immunoradiometric assay (IRMA) in conditioned medium from 25 of 40 cultures of bone-derived cells. PT HrP mRNA was detected in bone-derived cells by reverse transcriptase-l inked polymerase chain reaction (RT-PCR). The identity of PCR products was confirmed by Southern blotting. Local production of PTHrP in vivo may be important in the regulation of bone growth and remodelling.