Comparison of epi-GM3 with GM3 and GM1 as stimulators of neurite outgrowth. 
A variety of naturally occurring ganglioside structures were previously shown to be effective agents for inducing neurite outgrowth of primary neurons and neuroblastoma lines.  We report here the results of similar experiments with a synthetic epimer of GM3 (epi-GM3) possessing a neuraminidase-resistant beta-ketosidic linkage.  This substance was found to enhance neuritogenesis toward two transformed cell lines (neuro-2A, PC-12) and one primary neuronal tissue (dorsal root ganglia).  The results indicate that the stereochemistry of the ketoside linkage is not critical and that metabolism of exogenous ganglioside by the treated cells is not involved directly in the neuritogenic phenomenon.