HEPARIN ESSENTIAL FOR TISSUE-CULTURE WITH FISH FIBROBLAST GROWTH-FACTOR-2

Mitogenic activity of rainbow trout fibroblast growth factor 2 (rtFGF- 2) to RBCF-1 cell line was enhanced approximately 7-fold by the additi on of 10 ng/ml heparin, but decreased with excess heparin. This means that there is an optimum quantity of the exogenous heparin for the pot ential rtFGF-2 activity. On the other hand, heparin protected the rtFG F-2 from thermal denaturation and from the trypsin action. The rtFGF-2 was also proteolyzed in RBCF-1-conditioned medium, but not in the pre sence of heparin. These results suggest that heparin-like polysacchari des could play important roles to mediate and stabilize the activity o f FGF-2 in teleost. Furthermore, to culture cells sensitive to rtFGF-2 from various organs of fish in vitro, suitable amounts of heparin-lik e molecule are essential to uncover potential and stable rtFGF-2 activ ity.