Stimulation of division of Y1 adrenal cells by a growth factor isolated from bovine pituitary glands.

The effect of Fibroblast Growth Factor (FGF) on the initiation of DNA synthesis and on the rate of division of the Y1 adrenal cell line has been investigated. In sparse populations of Y1 cells (4 times 10- minus 3 cells/cm2) maintained in 0.2 percent calf serum, FGF was able to initiate DNA synthesis to the same extent that an optimal concentration of serum could. Cells maintained in 0.2 percent calf serum sustained continuous growth when given 5 ng/ml of FGF daily. Cultures fixed and stained with crystal violet showed FGF colonies to be of equivalent size and quantity as those with serum alone. Insulin had no mitogenic activity of its own at concentrations as high as 500 ng/ml nor did it have any potentiating effect on the mitogenic activity of FGF. Glucocorticoids (0.1 mug/ml to 1 mug/ml) inhibited (25 percent) the initiation of DNA synthesis as well as the rate of division induced by FGF. ACTH (0.75 IU/ml) was clearly inhibitory. Not only did it reduce the rate of division of cells in serum but it also reduced the rate of DNA synthesis and inhibited division in the presence of FGF.