we have established the patterns of ornithine decarboxylase activity ( an enzyme related to cell growth , differentiation , and proliferation ) during rat testicular development and studied the effect of epidermal growth factor ( egf ) , platelet-derived growth factor ( pdgf ) , transforming growth factor-type beta ( tgf-beta ) , and a serum-free , hormone/growth factor-supplemented medium ( tkm ) on ornithine decarboxylase ( odc ) activity in sertoli-spermatogenic cell cocultures and cultured seminiferous peritubular cells prepared from sexually immature rats ( 20-22 days old ) .
C0007589
differentiation
C0040690
transforming growth factor