The present invention provides a novel polypeptide, Connective Tissue Growth Factor (CTGF), polynucleotides encoding CTGF and polynucleotides regulating CTGF expression. The invention also provides agents that modulate CTGF and therapeutic methods for using the agents. Also provided are diagnostic methods for using CTGF and assays for identifying agents which affect the expression of CTGF polynucleotide.