Effects of insulin and retinoic acid on the anchorage-independent growth of transformed BHK21/C13 cells cultured with different lots of fetal bovine serum.

Several lots of fetal bovine serum (FBS) were divided into 2 groups; in one group, retinoic acid (RA) suppressed the anchorage-independent growth (AIG) of spontaneously transformed BHK21/C13 cells (clone Ag8-1) dose-dependently, but in the other group, little suppression occurred. In neither group of FBS was the anchorage-dependent growth (ADG) of the cells suppressed by RA. The addition of insulin enhanced the AIG of the cells in both groups even in the presence of RA. The 2 types of AIG systems in Ag8-1 cells, one susceptible and the other resistant to RA, are discussed.