[Presence of supposed growth factors in a serum fraction with a molecular weight of the components from 100,000 to 200,000 D].

Growth of cell culture BHK-21 in the presence of different fractions of bovine serum has been studied. Growth-promoting activity of the fraction with molecular weight of 100 000 daltons increased with the concentration of this fraction in the medium, but did not reach the activity level of the whole serum. The intensity of cell proliferation similar to that in the presence of the whole serum was achieved due to the combined action of the serum fraction with molecular weight of 100 000 - 200 000 daltons, containing the supposed growth factors and a fraction with low-molecular components of 14 000 daltons. When tested individually, neither of these two fractions showed similar effect.