EGF inhibits the differentiation of adipocyte precursors in primary cultures.

Adipocyte precursors, isolated from inguinal fat pads of 2-day old NBR rats, proliferate and differentiate in defined medium. EGF stimulates the proliferation of adipocyte precursors with an ED50 of 2 ng/ml and inhibits their differentiation with an ED50 of 0.45 ng/ml. EGF has no effect on differentiated adipocytes. EGF binding studies indicate that adipocyte precursors have two classes of receptors (Kd 4 X 10(-11) M, 4800 receptors/cell and Kd 1.4 X 10(-9) M, 22,000 receptors/cell). TGF-alpha has the same effect as EGF on adipocyte precursors. In contrast, basic and acidic FGF stimulate adipocyte precursor proliferation without inhibiting their differentiation.