Stimulierung von Kulturen embryonaler Rattenzellen durch eine Proteinfraktion aus fötalem Kälberserum : 1, Elektrophysiologische Messungen an den Oberflächenmembranen

Abstract

Normal embryonic rat cells incubated in serum-free medium accumulate in G1-phase of the cell cycle. On addition of a growth stimulating protein isoIated from fetal calf serum they are triggered to proceed through the cycle and they resume DNA synthesis 15 to 20 hour later. In this paper it is demonstrated that the surface membrane potential difference (PD) decreases immediately after changing serum-free medium against culture medium containing either calf serum or the isolated serum protein; the original PD is restored 2 to 3 hours later. Serumprotein without growth-stimulating activity does not affect the PD. A permanent rat cell line which grows independently of serum also has been tested. The PD of these cells is not significantly influenced by calf serum.