The present study was undertaken to investigate the effect of IGF-1 on proteoglycan (PG) synthesis and the autocrine/paracrine mechanisms involving insulin-like growth factor-1 (IGF-1) in the bovine coccygeal intervertebral disc.IGF-1 stimulated PG synthesis in cultured cells of nucleus pulposus of bovine intervertebral discs in a dose-dependent manner, and the effect was inhibited by an anti-IGF-1 monoclonal antibody.Insitu hybridization histochemistry revealed the expression of IGF-1 mRNA in the cultured cells, and IGF-1 production in these cells was demonstrated by radioimmunoassay.IGF-1 receptor in the cultured cells was also immunohistochemically demonstrated.The Scatchard analysis using an ^I-IGF-1 binding assay showed that the cells cultured in monolayer had a single type of IGF-1 receptor, whose affinity and number were estimated to be 7.38 x 10^8/M and 9.27 x 10^4/cell, respectively. These results suggest that IGF-1 stimulates PG synthesis in cells of the nucleus pulposus, and that these cells in culture have an IGF-1 autocrine/paracrine mechanism.The expressions of IGF-1 mRNA and IGF-1 receptor in disc tissue were greater in cells of the nucleus pulposus of fetal bovine intervertebral discs than in those of the adult discs.These findings suggest that the autocrine/paracrine IGF-1 action is more active in cells of young nucleus pulposus than in cells of matured subjects.富山医科薬科大学・博士(医学)・甲第240号・長田龍介・1996/3/8富山医科薬科大
