title: The serum-free growth of Balb/c 3T3 cells in medium supplemented with bovine colostrum.
abstract: Bovine milk contains growth promoting factors that stimulate DNA synthesis and cell division in confluent monolayers of quiescent Balb/c 3T3 cells. The growth factor activity was highest in colostrum obtained within 24 hours after birth of a calf. Samples of milk obtained 32 hours and 60 hours after birth were 20% and 1% as active respectively as was a sample obtained 8 hours after birth in stimulating DNA synthesis. No activity was detectable 3 days after birth or thereafter. A similar temporal dependence was found in sheep's milk. Bovine colostrum obtained on the day of a calf's birth can be substituted for serum and will support the growth of sparse Balb/c 3T3 cells to confluence. In Dulbecco's modified Eagles's medium (DMEM) supplemented with 2.5% (vol/vol) bovine colostrum, the number of Balb/c 3T3 cells in a dish increased 35-fold, from 2.0 X 10(4) cells to 7 X 10(5) cells. The generation time was approximately 38 hours. Proliferation of cells was characterized by formation of clusters of confluent Balb/c 3T3 cells which were smaller in size and more tightly packed than were Balb/c 3T3 cells grown to confluence in serum. No proliferation was detected in DMEM supplemented with milk obtained 10 days after birth of a calf or in DMEM supplemented with bovine serum albumen.
mesh_terms: D000818:Animals; D001769:Blood; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003126:Colostrum; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis; D005260:Female; D006133:Growth Substances / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008892:Milk; D011247:Pregnancy; D012756:Sheep
chemical_list: D003470:Culture Media; D006133:Growth Substances; D004247:DNA