SUBTYPE SWITCHING OF NATRIURETIC PEPTIDE RECEPTORS IN RAT CHONDROCYTES DURING IN-VITRO CULTURE

Subtype switching of natriuretic peptide receptor (NPR) during in vitro culture of rat chondrocytes was demonstrated by polymerase chain reaction (PCR) analysis, receptor binding assay, and the cGMP formation method. NPR-B was the predominant form in the receptor guanylate cyclase family (i.e. NPR-A and NPR-B) in both rat xiphoid cartilage and in its cultured cells. However, the chondrocytes began to express NPR-C at high levels when cultured in vitro and NPR-C became the major form (maximal binding capacity: 450 fmol/mg of protein) of NPR in the cultured cells. The abundantly expressed NPR-C had no effect on adenylate cyclase activity or proliferation of chondrocytes.