FIBROBLAST GROWTH-FACTOR (FGF-2) AND DELA YED INVOLUTION OF THE POSTERIOR LIMBS OF THE SLOW-WORM EMBRYO (ANGUIS-FRAGILIS, L)

Administration at doses of 1,800 ng to 6,200 ng of basic fibroblast gr owth factor (bFGF) around the posterior limb buds of young slow-worm ( Anguis fragilis, L.) embryos developing in cultured eggs has, after 4 to 6 days, in several embryos (10 among 15, treated at stage of allant oic bud, from 3 to 9 mm long), delayed the involution of these posteri or limbs: their anlagen are larger than the control ones and histologi cal examination shows an increase, between 20% and 30%, of cell densit y in the mesodermal component of the limb bud. These results bring int o light the possibility to control, to some degree, the regressive evo lution of the limbs.