Culturing of BHK-21 cells in a medium containing adult bovine serum and pituitary extract

Abstract

To achieve a comparable protein and cell production by culturing of BHK-21 cells in monolayer, in a medium containing adult bovine serum (ABS) and in a medium containing fetal bovine serum (FBS), 1.5 times (v/v) more ABS than FBS has to be added. At a volume fraction in the medium of less than 2% ABS, no proliferation is observed. For a fixed protein and cell production, the amount of required protein in a medium containing ABS can be reduced by addition of a protein extract from pituitary glands from calves (PEP). The relative cell density after 7 days in a culture medium containing 2 or 5% (v/v) ABS is 3 times higher when 0.2 g/liter pituitary extract is added. This indicates a synergistic interaction between components from ABS and from the protein extract. The addition of a pituitary extract to a medium with ABS also induces a prolonged cell proliferation period. A combined addition to a medium with ABS of 0.02 g/liter PEP and 0.15 g/liter heparin yields almost the same cell density as the addition of 0.2 g/liter PEP alone, indicating the presence of fibroblast growth factor (FGF) in the pituitary extract. However, the enhanced cell production by the addition of a pituitary extract to a medium containing ABS cannot be explained only by the presence in this crude extract of a- or bFGF.