in order to ask whether cells grown in serum-free medium are phenotypically identical to cells grown in serum , we examined effects of cell growth under both conditions on the beta-adrenergic receptor , a cell surface marker that activates adenylate cyclase and thereby regulates these cells . beta-adrenergic receptors were qualitatively similar in cells grown in serum-containing and serum-free media , but the number of receptors was 30-50 % less in cells grown with serum .
C0699040
cell surface
C0007634
cells